Phase 6 abgeschlossen: Aktenchat, Kanäle, Echtzeit, Benachrichtigungen

Ein Ereignisstrom mit Themen (/api/stream), in dem der Dateistrom aus Phase 5
aufgegangen ist. Zwei Prüfungen: beim Verbinden, welche Themen der Nutzer
abonnieren darf, und je Ereignis wird der Inhalt mit seinen Rechten geladen.
Das zweite ist nicht nur Vorsicht — eine Umklassifizierung wirkt dadurch in
einer offenen Verbindung sofort. In der pg_notify-Nutzlast steht nie ein
Inhalt, nur Thema, Art und Kennung.

Der Aktenchat sendet optimistisch mit clientseitiger UUIDv7, die zugleich
Idempotenzschlüssel ist. Antworten, vier feste Reaktionen, Bearbeiten mit
sichtbarem editedAt, Zurückziehen mit Platzhalter — Löschen gibt es nicht, und
eine Regel in der Datenbank hält das fest. Eine zurückgezogene Nachricht kommt
ohne Text an, nicht ausgeblendet.

Aktenzeichen im Text werden zu Vorschaukarten, serverseitig aufgelöst. Eine
Akte, die der Leser nicht sehen darf, sieht darin genauso aus wie eine, die es
gar nicht gibt.

"Als Vermerk übernehmen" steht sichtbar an jeder Nachricht. Der Vermerk gehört
dem Verfasser, nicht dem Übernehmenden; ein Systemeintrag nennt den Ursprung,
damit der Wortlaut später nicht für die Akte geschrieben wirkt.

Bei den Discord-Benachrichtigungen entscheidet die Web-App, wer was erfährt,
und der Worker liefert nur aus. Die Alternative hätte geheissen, die
Sichtbarkeitsprüfung im Worker ein zweites Mal zu bauen. In meta steht ein
Titel nur, wenn er hinaus darf — ab Stufe 3 keiner. Postausgang als Tabelle,
angestossen über LISTEN, mit Takt als Sicherheitsnetz.

Nebenbei riss das Budget der Fallakte erneut (122 kB). Drei Schritte zurück
auf 119,6: Chattexte in eine eigene i18n-Datei, ein gemeinsames AddPanel statt
viermal derselbe Aufklapp-Code, und eine eigene UUIDv7 statt des Pakets — die
Sortierbarkeit, auf der die Nachlieferung beruht, steht damit im eigenen Code
und hat Tests.

Unterwegs habe ich NotifyMode und User.notifyMode ein zweites Mal angelegt,
obwohl es beides seit dem Grundgerüst gibt. Die Migration schlug fehl und die
Datenbank musste von Hand aufgeräumt werden; die Lehre steht in docs/13.

155 Tests im Web-Paket, 15 in der Datenbank, 7 im Worker, 32 e2e.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

web/app/(app)/chat/actions.ts

@@ -0,0 +1,128 @@
+'use server'
+
+import { revalidatePath } from 'next/cache'
+import { z } from 'zod'
+import { requireUser } from '@/lib/auth/current'
+import { AccessError } from '@/lib/errors'
+import {
+  adoptAsEntry,
+  editMessage,
+  markRead,
+  sendMessage,
+  toggleReaction,
+  withdrawMessage,
+} from '@/lib/chat/service'
+import { REACTIONS } from '@/lib/chat/terms'
+import { de } from '@/lib/i18n/de'
+
+export type ActionResult = { ok: true } | { ok: false; error: string }
+
+function toMessage(error: unknown): string {
+  if (error instanceof AccessError) {
+    return de.actionErrors[error.code] ?? de.actionErrors.default!
+  }
+  console.error('[chat] unerwartet', error)
+  return de.actionErrors.default!
+}
+
+const scope = z.union([
+  z.object({ kind: z.literal('case'), caseNumber: z.string().min(1) }),
+  z.object({ kind: z.literal('channel'), key: z.string().min(1) }),
+])
+
+const sendSchema = z.object({
+  id: z.string().min(1).max(64),
+  scope,
+  body: z.string().min(1).max(4000),
+  replyToId: z.string().max(64).nullish(),
+})
+
+export async function sendMessageAction(input: unknown): Promise<ActionResult> {
+  const user = await requireUser()
+  const parsed = sendSchema.safeParse(input)
+  if (!parsed.success) return { ok: false, error: de.actionErrors['message-empty']! }
+
+  try {
+    await sendMessage(user.permissions, parsed.data)
+    return { ok: true }
+  } catch (error) {
+    return { ok: false, error: toMessage(error) }
+  }
+}
+
+const editSchema = z.object({ id: z.string().min(1), body: z.string().min(1).max(4000) })
+
+export async function editMessageAction(input: unknown): Promise<ActionResult> {
+  const user = await requireUser()
+  const parsed = editSchema.safeParse(input)
+  if (!parsed.success) return { ok: false, error: de.actionErrors['message-empty']! }
+
+  try {
+    await editMessage(user.permissions, parsed.data)
+    return { ok: true }
+  } catch (error) {
+    return { ok: false, error: toMessage(error) }
+  }
+}
+
+const idSchema = z.object({ id: z.string().min(1) })
+
+export async function withdrawMessageAction(input: unknown): Promise<ActionResult> {
+  const user = await requireUser()
+  const parsed = idSchema.safeParse(input)
+  if (!parsed.success) return { ok: false, error: de.actionErrors.default! }
+
+  try {
+    await withdrawMessage(user.permissions, parsed.data.id)
+    return { ok: true }
+  } catch (error) {
+    return { ok: false, error: toMessage(error) }
+  }
+}
+
+const reactionSchema = z.object({ id: z.string().min(1), key: z.enum(REACTIONS) })
+
+export async function toggleReactionAction(input: unknown): Promise<ActionResult> {
+  const user = await requireUser()
+  const parsed = reactionSchema.safeParse(input)
+  if (!parsed.success) return { ok: false, error: de.actionErrors.default! }
+
+  try {
+    await toggleReaction(user.permissions, parsed.data)
+    return { ok: true }
+  } catch (error) {
+    return { ok: false, error: toMessage(error) }
+  }
+}
+
+/**
+ * „Als Vermerk übernehmen". Danach wird die Akte neu geladen: der Vermerk
+ * gehört in den Verlauf, und der steht auf derselben Seite.
+ */
+export async function adoptAsEntryAction(input: unknown): Promise<ActionResult> {
+  const user = await requireUser()
+  const parsed = idSchema.safeParse(input)
+  if (!parsed.success) return { ok: false, error: de.actionErrors.default! }
+
+  try {
+    await adoptAsEntry(user.permissions, parsed.data.id)
+    revalidatePath('/faelle', 'layout')
+    return { ok: true }
+  } catch (error) {
+    return { ok: false, error: toMessage(error) }
+  }
+}
+
+const readSchema = z.object({
+  scopeType: z.enum(['case', 'channel']),
+  scopeId: z.string().min(1),
+})
+
+export async function markReadAction(input: unknown): Promise<ActionResult> {
+  const user = await requireUser()
+  const parsed = readSchema.safeParse(input)
+  if (!parsed.success) return { ok: false, error: de.actionErrors.default! }
+
+  await markRead(user.permissions, parsed.data.scopeType, parsed.data.scopeId)
+  return { ok: true }
+}

web/app/(app)/dokumente/[documentNumber]/page.tsx

@@ -47,6 +47,7 @@ async function Body({
     title: string
     layout: string
     createdAt: Date
+    caseId: string | null
   }
   permissions: EffectivePermissions
   canEdit: boolean
@@ -69,6 +70,7 @@ async function Body({
       sections={sections}
       canEdit={canEdit}
       documentNumber={document.documentNumber}
+      topic={document.caseId ? `case:${document.caseId}` : `user:${permissions.userId}`}
       photoUrls={photoUrls}
     />
   )
@@ -108,11 +110,13 @@ async function Body({
 async function AttachmentBlock({
   documentId,
   documentNumber,
+  topic,
   permissions,
   canUpload,
 }: {
   documentId: string
   documentNumber: string
+  topic: string
   permissions: EffectivePermissions
   canUpload: boolean
 }) {
@@ -120,6 +124,7 @@ async function AttachmentBlock({
   return (
     <Attachments
       target={{ documentNumber }}
+      topic={topic}
       initial={toAttachmentViews(anhaenge)}
       canUpload={canUpload}
       canRelease={permissions.isAdmin}
@@ -274,6 +279,7 @@ export default async function DocumentPage({
             <AttachmentBlock
               documentId={doc.id}
               documentNumber={doc.documentNumber}
+              topic={doc.caseId ? `case:${doc.caseId}` : `user:${user.id}`}
               permissions={user.permissions}
               canUpload={canEdit}
             />

web/app/(app)/einstellungen/NotifyForm.tsx

@@ -0,0 +1,46 @@
+'use client'
+
+import { useActionState } from 'react'
+import { notifyText } from '@/lib/i18n/shell'
+import { saveNotifyModeAction, type ActionResult } from './actions'
+
+const MODES = ['ALL', 'OWN_CASES', 'MENTIONS', 'OFF'] as const
+
+export function NotifyForm({ current }: { current: string }) {
+  const [state, action, pending] = useActionState<ActionResult | null, FormData>(
+    saveNotifyModeAction,
+    null,
+  )
+
+  return (
+    <form action={action} className="mt-6">
+      <fieldset>
+        <legend className="font-condensed text-xs text-text-dim">{notifyText.mode}</legend>
+        <div className="mt-3 space-y-2">
+          {MODES.map((mode) => (
+            <label key={mode} className="flex items-center gap-3 text-sm">
+              <input type="radio" name="notifyMode" value={mode} defaultChecked={current === mode} />
+              {notifyText.modes[mode]}
+            </label>
+          ))}
+        </div>
+      </fieldset>
+
+      <div className="mt-5 flex items-center gap-3">
+        <button
+          type="submit"
+          disabled={pending}
+          className="border border-line bg-raised px-4 py-2 font-condensed text-xs text-accent disabled:text-text-dim"
+        >
+          {notifyText.save}
+        </button>
+        {state?.ok ? (
+          <span className="font-condensed text-2xs text-text-dim">{notifyText.saved}</span>
+        ) : null}
+        {state && !state.ok ? (
+          <span className="font-condensed text-2xs text-stamp-4">{state.error}</span>
+        ) : null}
+      </div>
+    </form>
+  )
+}

web/app/(app)/einstellungen/actions.ts

@@ -0,0 +1,28 @@
+'use server'
+
+import { revalidatePath } from 'next/cache'
+import { z } from 'zod'
+import { db } from '@/lib/db'
+import { requireUser } from '@/lib/auth/current'
+import { de } from '@/lib/i18n/de'
+
+export type ActionResult = { ok: true } | { ok: false; error: string }
+
+const schema = z.object({ notifyMode: z.enum(['ALL', 'OWN_CASES', 'MENTIONS', 'OFF']) })
+
+/** Jeder stellt nur für sich selbst ein — die Kennung kommt aus der Sitzung. */
+export async function saveNotifyModeAction(
+  _prev: ActionResult | null,
+  formData: FormData,
+): Promise<ActionResult> {
+  const user = await requireUser()
+  const parsed = schema.safeParse(Object.fromEntries(formData))
+  if (!parsed.success) return { ok: false, error: de.actionErrors.default! }
+
+  await db.user.update({
+    where: { id: user.id },
+    data: { notifyMode: parsed.data.notifyMode },
+  })
+  revalidatePath('/einstellungen')
+  return { ok: true }
+}

web/app/(app)/einstellungen/page.tsx

@@ -0,0 +1,24 @@
+import type { Metadata } from 'next'
+import { db } from '@/lib/db'
+import { requireUser } from '@/lib/auth/current'
+import { de } from '@/lib/i18n/de'
+import { NotifyForm } from './NotifyForm'
+
+export const metadata: Metadata = { title: de.notify.heading }
+export const dynamic = 'force-dynamic'
+
+export default async function SettingsPage() {
+  const user = await requireUser()
+  const eigen = await db.user.findUniqueOrThrow({
+    where: { id: user.id },
+    select: { notifyMode: true },
+  })
+
+  return (
+    <main className="mx-auto max-w-(--container-measure) px-6 py-10">
+      <h1 className="font-condensed">{de.notify.heading}</h1>
+      <p className="mt-2 text-sm text-text-dim">{de.notify.intro}</p>
+      <NotifyForm current={eigen.notifyMode} />
+    </main>
+  )
+}

web/app/(app)/faelle/[caseNumber]/CaseLinks.tsx

@@ -3,10 +3,10 @@
 import { useState, useTransition } from 'react'
 import Link from 'next/link'
 import { linkText } from '@/lib/i18n/cases'
-import { commonText } from '@/lib/i18n/common'
 import { LINK_KINDS } from '@/lib/cases/terms'
-import { linkCasesAction, unlinkCasesAction } from '../actions'
+import { AddPanel, PanelSelect } from '@/components/AddPanel'
 import { classificationEdgeStyle } from '@/components/StampMark'
+import { linkCasesAction, unlinkCasesAction } from '../actions'
 
 type Verknuepfung = {
   kind: string
@@ -29,10 +29,9 @@ export function CaseLinks({
   links: Verknuepfung[]
   canEdit: boolean
 }) {
-  const [open, setOpen] = useState(false)
   const [target, setTarget] = useState('')
   const [kind, setKind] = useState<string>('RELATED')
-  const [error, setError] = useState<string | null>(null)
+  const [fehler, setFehler] = useState<string | null>(null)
   const [pending, startTransition] = useTransition()
 
   return (
@@ -65,12 +64,12 @@ export function CaseLinks({
                   disabled={pending}
                   onClick={() =>
                     startTransition(async () => {
-                      const result = await unlinkCasesAction({
+                      const ergebnis = await unlinkCasesAction({
                         fromCaseNumber: caseNumber,
                         toCaseNumber: link.other.caseNumber,
                         kind: link.kind,
                       })
-                      if (!result.ok) setError(result.error)
+                      if (!ergebnis.ok) setFehler(ergebnis.error)
                     })
                   }
                   className="font-condensed text-2xs text-text-dim"
@@ -83,70 +82,37 @@ export function CaseLinks({
         </ul>
       )}
 
-      {error ? <p className="mt-2 font-condensed text-2xs text-stamp-4">{error}</p> : null}
+      {fehler ? <p className="mt-2 font-condensed text-2xs text-stamp-4">{fehler}</p> : null}
 
       {canEdit ? (
-        open ? (
-          <div className="mt-4 flex flex-wrap items-center gap-2">
-            <select
-              value={kind}
-              onChange={(event) => setKind(event.target.value)}
-              aria-label={linkText.kind}
-              className="border border-line bg-raised px-2 py-1 text-2xs"
-            >
-              {LINK_KINDS.map((value) => (
-                <option key={value} value={value}>
-                  {linkText.kinds[value] ?? value}
-                </option>
-              ))}
-            </select>
-            <input
-              value={target}
-              onChange={(event) => setTarget(event.target.value)}
-              placeholder={linkText.target}
-              aria-label={linkText.target}
-              className="border border-line bg-raised px-2 py-1 font-mono text-2xs"
-            />
-            <button
-              type="button"
-              disabled={pending || target.trim() === ''}
-              onClick={() =>
-                startTransition(async () => {
-                  setError(null)
-                  const result = await linkCasesAction({
-                    fromCaseNumber: caseNumber,
-                    toCaseNumber: target.trim(),
-                    kind,
-                  })
-                  if (result.ok) {
-                    setTarget('')
-                    setOpen(false)
-                  } else {
-                    setError(result.error)
-                  }
-                })
-              }
-              className="border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent disabled:text-text-dim"
-            >
-              {linkText.add}
-            </button>
-            <button
-              type="button"
-              onClick={() => setOpen(false)}
-              className="font-condensed text-2xs text-text-dim"
-            >
-              {commonText.cancel}
-            </button>
-          </div>
-        ) : (
-          <button
-            type="button"
-            onClick={() => setOpen(true)}
-            className="mt-4 border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent"
-          >
-            {linkText.add}
-          </button>
-        )
+        <AddPanel
+          label={linkText.add}
+          disabled={target.trim() === ''}
+          onSubmit={async () => {
+            const ergebnis = await linkCasesAction({
+              fromCaseNumber: caseNumber,
+              toCaseNumber: target.trim(),
+              kind,
+            })
+            if (ergebnis.ok) setTarget('')
+            return ergebnis
+          }}
+        >
+          <PanelSelect value={kind} onChange={setKind} label={linkText.kind}>
+            {LINK_KINDS.map((value) => (
+              <option key={value} value={value}>
+                {linkText.kinds[value] ?? value}
+              </option>
+            ))}
+          </PanelSelect>
+          <input
+            value={target}
+            onChange={(event) => setTarget(event.target.value)}
+            placeholder={linkText.target}
+            aria-label={linkText.target}
+            className="border border-line bg-raised px-2 py-1 font-mono text-2xs"
+          />
+        </AddPanel>
       ) : null}
     </div>
   )

web/app/(app)/faelle/[caseNumber]/EntryComposer.tsx

@@ -1,7 +1,7 @@
 'use client'
 
 import { useOptimistic, useRef, useState, useTransition } from 'react'
-import { uuidv7 } from 'uuidv7'
+import { uuidv7 } from '@/lib/uuidv7'
 import { caseText, entryText } from '@/lib/i18n/cases'
 import { addEntryAction } from '../actions'
 

web/app/(app)/faelle/[caseNumber]/Participants.tsx

@@ -2,9 +2,10 @@
 
 import { useState, useTransition } from 'react'
 import Link from 'next/link'
-import { participantText } from '@/lib/i18n/cases'
 import { commonText } from '@/lib/i18n/common'
+import { participantText } from '@/lib/i18n/cases'
 import { PARTICIPANT_ROLES } from '@/lib/cases/terms'
+import { AddPanel, PanelSelect } from '@/components/AddPanel'
 import { addParticipantAction, removeParticipantAction } from '../actions'
 
 type Beteiligter = {
@@ -35,31 +36,11 @@ export function Participants({
   members: { id: string; displayName: string }[]
   files: { id: string; displayName: string }[]
 }) {
-  const [open, setOpen] = useState(false)
   const [role, setRole] = useState<string>('INVESTIGATOR')
   const [target, setTarget] = useState('')
-  const [error, setError] = useState<string | null>(null)
+  const [fehler, setFehler] = useState<string | null>(null)
   const [pending, startTransition] = useTransition()
 
-  function add() {
-    if (!target) return
-    setError(null)
-    const [art, id] = target.split(':')
-    startTransition(async () => {
-      const result = await addParticipantAction({
-        caseNumber,
-        role,
-        ...(art === 'user' ? { userId: id } : { personnelFileId: id }),
-      })
-      if (result.ok) {
-        setTarget('')
-        setOpen(false)
-      } else {
-        setError(result.error)
-      }
-    })
-  }
-
   return (
     <div>
       {participants.length === 0 ? (
@@ -89,11 +70,11 @@ export function Participants({
                   disabled={pending}
                   onClick={() =>
                     startTransition(async () => {
-                      const result = await removeParticipantAction({
+                      const ergebnis = await removeParticipantAction({
                         caseNumber,
                         participantId: person.id,
                       })
-                      if (!result.ok) setError(result.error)
+                      if (!ergebnis.ok) setFehler(ergebnis.error)
                     })
                   }
                   className="font-condensed text-2xs text-text-dim"
@@ -106,75 +87,49 @@ export function Participants({
         </ul>
       )}
 
-      {error ? <p className="mt-2 font-condensed text-2xs text-stamp-4">{error}</p> : null}
+      {fehler ? <p className="mt-2 font-condensed text-2xs text-stamp-4">{fehler}</p> : null}
 
       {canEdit ? (
-        open ? (
-          <div className="mt-4 border border-line p-3">
-            <p className="max-w-(--container-measure) text-2xs text-text-dim">
-              {participantText.hint}
-            </p>
-            <div className="mt-3 flex flex-wrap items-center gap-2">
-              <select
-                value={role}
-                onChange={(event) => setRole(event.target.value)}
-                aria-label={participantText.role}
-                className="border border-line bg-raised px-2 py-1 text-2xs"
-              >
-                {PARTICIPANT_ROLES.map((value) => (
-                  <option key={value} value={value}>
-                    {participantText.roles[value] ?? value}
-                  </option>
-                ))}
-              </select>
-              <select
-                value={target}
-                onChange={(event) => setTarget(event.target.value)}
-                aria-label={participantText.person}
-                className="border border-line bg-raised px-2 py-1 text-2xs"
-              >
-                <option value="">—</option>
-                <optgroup label={participantText.pickUser}>
-                  {members.map((member) => (
-                    <option key={member.id} value={`user:${member.id}`}>
-                      {member.displayName}
-                    </option>
-                  ))}
-                </optgroup>
-                <optgroup label={participantText.pickPersonnel}>
-                  {files.map((file) => (
-                    <option key={file.id} value={`file:${file.id}`}>
-                      {file.displayName}
-                    </option>
-                  ))}
-                </optgroup>
-              </select>
-              <button
-                type="button"
-                disabled={pending || !target}
-                onClick={add}
-                className="border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent disabled:text-text-dim"
-              >
-                {participantText.add}
-              </button>
-              <button
-                type="button"
-                onClick={() => setOpen(false)}
-                className="font-condensed text-2xs text-text-dim"
-              >
-                {commonText.cancel}
-              </button>
-            </div>
-          </div>
-        ) : (
-          <button
-            type="button"
-            onClick={() => setOpen(true)}
-            className="mt-4 border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent"
-          >
-            {participantText.add}
-          </button>
-        )
+        <AddPanel
+          label={participantText.add}
+          hint={participantText.hint}
+          disabled={!target}
+          onSubmit={async () => {
+            const [art, id] = target.split(':')
+            const ergebnis = await addParticipantAction({
+              caseNumber,
+              role,
+              ...(art === 'user' ? { userId: id } : { personnelFileId: id }),
+            })
+            if (ergebnis.ok) setTarget('')
+            return ergebnis
+          }}
+        >
+          <PanelSelect value={role} onChange={setRole} label={participantText.role}>
+            {PARTICIPANT_ROLES.map((value) => (
+              <option key={value} value={value}>
+                {participantText.roles[value] ?? value}
+              </option>
+            ))}
+          </PanelSelect>
+          <PanelSelect value={target} onChange={setTarget} label={participantText.person}>
+            <option value="">—</option>
+            <optgroup label={participantText.pickUser}>
+              {members.map((member) => (
+                <option key={member.id} value={`user:${member.id}`}>
+                  {member.displayName}
+                </option>
+              ))}
+            </optgroup>
+            <optgroup label={participantText.pickPersonnel}>
+              {files.map((file) => (
+                <option key={file.id} value={`file:${file.id}`}>
+                  {file.displayName}
+                </option>
+              ))}
+            </optgroup>
+          </PanelSelect>
+        </AddPanel>
       ) : null}
     </div>
   )

web/app/(app)/faelle/[caseNumber]/page.tsx

@@ -25,6 +25,8 @@ import { visiblePersonnelWhere } from '@/lib/access/personnelFilter'
 import { DocumentList } from '@/components/documents/DocumentList'
 import { NewDocument } from '@/components/documents/NewDocument'
 import { Attachments } from '@/components/files/Attachments'
+import { ChatLazy } from '@/components/chat/ChatLazy'
+import { loadChatView } from '@/lib/chat/load'
 import { listAttachments } from '@/lib/files/service'
 import { toAttachmentViews } from '@/lib/files/view'
 import { allowedTargets, type CaseStatusName } from '@/lib/cases/lifecycle'
@@ -214,6 +216,7 @@ async function Relations({
         <div className="mt-4">
           <Attachments
             target={{ caseNumber: akte.caseNumber }}
+            topic={`case:${akte.id}`}
             initial={toAttachmentViews(anhaenge)}
             canUpload={canEdit}
             canRelease={permissions.isAdmin}
@@ -239,6 +242,36 @@ async function Relations({
   )
 }
 
+/**
+ * Der Aktenchat. Eigene Suspense-Grenze, weil er die meisten Abfragen macht
+ * und der Rest der Seite nicht auf ihn warten soll.
+ */
+async function ChatBlock({
+  akte,
+  user,
+}: {
+  akte: { id: string; caseNumber: string; status: string; classification: number }
+  user: { id: string; permissions: EffectivePermissions }
+}) {
+  const ansicht = await loadChatView(user.permissions, {
+    kind: 'case',
+    caseNumber: akte.caseNumber,
+  })
+
+  return (
+    <ChatLazy
+      scope={{ kind: 'case', caseNumber: akte.caseNumber, caseId: akte.id }}
+      topic={`case:${akte.id}`}
+      initial={ansicht.messages}
+      initialReactions={ansicht.reactions}
+      currentUserId={user.id}
+      lastReadAt={ansicht.lastReadAt}
+      canAdopt={canEditCase(user.permissions, akte, 'entry.create').ok}
+      mentionNames={ansicht.mentionNames}
+    />
+  )
+}
+
 async function SectionBlock({
   caseId,
   caseNumber,
@@ -373,6 +406,20 @@ export default async function CasePage({
         </Suspense>
       </div>
 
+      <section className="mt-12">
+        <Suspense
+          fallback={
+            <div className="space-y-3 border border-line p-4">
+              <SkeletonLine width="8rem" />
+              <SkeletonLine width="70%" />
+              <SkeletonLine width="55%" />
+            </div>
+          }
+        >
+          <ChatBlock akte={akte} user={user} />
+        </Suspense>
+      </section>
+
       <nav className="mt-12 flex gap-4 border-b border-line pb-2 font-condensed text-xs">
         <span className="text-text-dim">{de.case.timeline}</span>
         <Link href={`/faelle/${akte.caseNumber}/aenderungen`}>{de.case.changes}</Link>

web/app/(app)/kanaele/NewChannelForm.tsx

@@ -0,0 +1,116 @@
+'use client'
+
+import { useActionState, useState } from 'react'
+import { channelText } from '@/lib/i18n/chat'
+import { clearanceText, commonText } from '@/lib/i18n/common'
+import { createChannelAction, type ActionResult } from './actions'
+
+export function NewChannelForm({ levels }: { levels: { level: number; name: string }[] }) {
+  const [offen, setOffen] = useState(false)
+  const [state, action, pending] = useActionState<ActionResult | null, FormData>(
+    createChannelAction,
+    null,
+  )
+
+  if (!offen) {
+    return (
+      <button
+        type="button"
+        onClick={() => setOffen(true)}
+        className="border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent"
+      >
+        {channelText.create}
+      </button>
+    )
+  }
+
+  return (
+    <form action={action} className="max-w-(--container-measure) border border-line p-4">
+      <p className="font-condensed text-xs text-text-dim">{channelText.createTitle}</p>
+
+      <div className="mt-3 grid gap-4 sm:grid-cols-2">
+        <div>
+          <label htmlFor="name" className="font-condensed text-2xs text-text-dim">
+            {channelText.name}
+          </label>
+          <input
+            id="name"
+            name="name"
+            required
+            minLength={2}
+            maxLength={120}
+            className="mt-1 block w-full border border-line bg-raised px-3 py-2 text-sm"
+          />
+        </div>
+
+        <div>
+          <label htmlFor="key" className="font-condensed text-2xs text-text-dim">
+            {channelText.key}
+          </label>
+          <input
+            id="key"
+            name="key"
+            required
+            pattern="[a-z0-9][a-z0-9-]{1,40}"
+            className="mt-1 block w-full border border-line bg-raised px-3 py-2 font-mono text-sm"
+          />
+          <p className="mt-1 text-2xs text-text-dim">{channelText.keyHint}</p>
+        </div>
+
+        <div className="sm:col-span-2">
+          <label htmlFor="description" className="font-condensed text-2xs text-text-dim">
+            {channelText.description}
+          </label>
+          <input
+            id="description"
+            name="description"
+            maxLength={500}
+            className="mt-1 block w-full border border-line bg-raised px-3 py-2 text-sm"
+          />
+        </div>
+
+        <div>
+          <label htmlFor="minClearance" className="font-condensed text-2xs text-text-dim">
+            {channelText.minClearance}
+          </label>
+          <select
+            id="minClearance"
+            name="minClearance"
+            defaultValue={0}
+            className="mt-1 block w-full border border-line bg-raised px-3 py-2 text-sm"
+          >
+            {levels.map((level) => (
+              <option key={level.level} value={level.level}>
+                {level.level} · {level.name}
+              </option>
+            ))}
+          </select>
+          <p className="mt-1 text-2xs text-text-dim">
+            {channelText.minClearanceHint} {clearanceText.label}
+          </p>
+        </div>
+      </div>
+
+      {state && !state.ok ? (
+        <p className="mt-3 font-condensed text-2xs text-stamp-4">{state.error}</p>
+      ) : null}
+
+      <div className="mt-4 flex gap-3">
+        <button
+          type="submit"
+          disabled={pending}
+          className="border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent disabled:text-text-dim"
+        >
+          {pending ? commonText.loading : channelText.create}
+        </button>
+        <button
+          type="button"
+          onClick={() => setOffen(false)}
+          className="font-condensed text-2xs text-text-dim"
+        >
+          {commonText.cancel}
+        </button>
+      </div>
+    </form>
+  )
+}

web/app/(app)/kanaele/[key]/page.tsx

@@ -0,0 +1,70 @@
+import type { Metadata } from 'next'
+import { notFound } from 'next/navigation'
+import { requireUser } from '@/lib/auth/current'
+import { AccessError } from '@/lib/errors'
+import { loadChatView } from '@/lib/chat/load'
+import { db } from '@/lib/db'
+import { visibleChannelWhere } from '@/lib/access/chatFilter'
+import { de } from '@/lib/i18n/de'
+import { Chat } from '@/components/chat/Chat'
+
+export const dynamic = 'force-dynamic'
+
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ key: string }>
+}): Promise<Metadata> {
+  const { key } = await params
+  return { title: `#${key}` }
+}
+
+export default async function ChannelPage({ params }: { params: Promise<{ key: string }> }) {
+  const user = await requireUser()
+  const { key } = await params
+
+  const kanal = await db.channel.findFirst({
+    where: { AND: [visibleChannelWhere(user.permissions), { key, isArchived: false }] },
+    select: { id: true, key: true, name: true, description: true },
+  })
+  // Kein Zugriff heisst 404.
+  if (!kanal) notFound()
+
+  let ansicht
+  try {
+    ansicht = await loadChatView(user.permissions, { kind: 'channel', key: kanal.key })
+  } catch (error) {
+    if (error instanceof AccessError) notFound()
+    throw error
+  }
+
+  return (
+    <main className="mx-auto max-w-5xl px-6 py-10">
+      <header>
+        <span className="font-mono text-xs text-text-dim">#{kanal.key}</span>
+        <h1 className="mt-1 font-condensed">{kanal.name}</h1>
+        {kanal.description ? (
+          <p className="mt-2 max-w-(--container-measure) text-sm text-text-dim">
+            {kanal.description}
+          </p>
+        ) : null}
+      </header>
+
+      <div className="mt-8">
+        <Chat
+          scope={{ kind: 'channel', key: kanal.key, channelId: kanal.id }}
+          topic={`channel:${kanal.id}`}
+          initial={ansicht.messages}
+          initialReactions={ansicht.reactions}
+          currentUserId={user.id}
+          lastReadAt={ansicht.lastReadAt}
+          // Ein Vermerk gehört in eine Akte. Ein Kanal hat keine.
+          canAdopt={false}
+          mentionNames={ansicht.mentionNames}
+        />
+      </div>
+
+      <p className="mt-4 text-2xs text-text-dim">{de.chat.hint}</p>
+    </main>
+  )
+}

web/app/(app)/kanaele/actions.ts

@@ -0,0 +1,40 @@
+'use server'
+
+import { redirect } from 'next/navigation'
+import { z } from 'zod'
+import { requireUser } from '@/lib/auth/current'
+import { AccessError } from '@/lib/errors'
+import { createChannel } from '@/lib/chat/service'
+import { de } from '@/lib/i18n/de'
+
+export type ActionResult = { ok: true } | { ok: false; error: string }
+
+const schema = z.object({
+  key: z.string().min(2).max(40),
+  name: z.string().min(2).max(120),
+  description: z.string().max(500).optional(),
+  minClearance: z.coerce.number().int().min(0).max(5),
+})
+
+export async function createChannelAction(
+  _prev: ActionResult | null,
+  formData: FormData,
+): Promise<ActionResult> {
+  const user = await requireUser()
+  const parsed = schema.safeParse(Object.fromEntries(formData))
+  if (!parsed.success) return { ok: false, error: de.actionErrors.default! }
+
+  let key: string
+  try {
+    const kanal = await createChannel(user.permissions, parsed.data)
+    key = kanal.key
+  } catch (error) {
+    if (error instanceof AccessError) {
+      return { ok: false, error: de.actionErrors[error.code] ?? de.actionErrors.default! }
+    }
+    console.error('[kanaele] unerwartet', error)
+    return { ok: false, error: de.actionErrors.default! }
+  }
+
+  redirect(`/kanaele/${key}`)
+}

web/app/(app)/kanaele/page.tsx

@@ -0,0 +1,71 @@
+import type { Metadata } from 'next'
+import Link from 'next/link'
+import { db } from '@/lib/db'
+import { requireUser } from '@/lib/auth/current'
+import { listChannels } from '@/lib/chat/service'
+import { de } from '@/lib/i18n/de'
+import { StampMark } from '@/components/StampMark'
+import { NewChannelForm } from './NewChannelForm'
+
+export const metadata: Metadata = { title: de.channel.heading }
+export const dynamic = 'force-dynamic'
+
+/**
+ * Freie Kanäle: Räume für Absprachen, die zu keiner Akte gehören.
+ *
+ * Ein Kanal über der Stufe des Lesers taucht nicht auf. Anders als bei Akten
+ * ist die Existenz eines Kanals aber kein Geheimnis für die, die seine Stufe
+ * haben — ein Raum, den man erraten müsste, wäre keiner.
+ */
+export default async function ChannelListPage() {
+  const user = await requireUser()
+
+  const [kanaele, levels] = await Promise.all([
+    listChannels(user.permissions),
+    db.clearanceLevelConfig.findMany({ orderBy: { level: 'asc' } }),
+  ])
+  const levelName = new Map(levels.map((l) => [l.level, l.name]))
+  const darfAnlegen = user.permissions.isAdmin || user.permissions.permissions.has('case.create')
+
+  return (
+    <main className="mx-auto max-w-5xl px-6 py-10">
+      <h1 className="font-condensed">{de.channel.heading}</h1>
+      <p className="mt-2 max-w-(--container-measure) text-sm text-text-dim">
+        {de.channel.intro}
+      </p>
+
+      {kanaele.length === 0 ? (
+        <p className="mt-10 text-text-dim">{de.channel.empty}</p>
+      ) : (
+        <ul className="mt-6 border-t border-line">
+          {kanaele.map((kanal) => (
+            <li key={kanal.id} className="border-b border-line">
+              <Link
+                href={`/kanaele/${kanal.key}`}
+                prefetch
+                className="flex flex-wrap items-baseline gap-x-4 gap-y-1 py-3 text-text no-underline"
+              >
+                <span className="font-mono text-xs text-text-dim">#{kanal.key}</span>
+                <span className="grow">{kanal.name}</span>
+                {kanal.minClearance > 0 ? (
+                  <StampMark
+                    level={kanal.minClearance}
+                    name={levelName.get(kanal.minClearance) ?? de.common.unknown}
+                  />
+                ) : null}
+              </Link>
+            </li>
+          ))}
+        </ul>
+      )}
+
+      {darfAnlegen ? (
+        <div className="mt-8">
+          <NewChannelForm
+            levels={levels.filter((l) => l.level <= user.permissions.clearanceLevel)}
+          />
+        </div>
+      ) : null}
+    </main>
+  )
+}

web/app/(app)/layout.tsx

@@ -25,6 +25,8 @@ export default async function AppLayout({ children }: { children: React.ReactNod
             {user.permissions.isAdmin || user.permissions.permissions.has('personnel.read') ? (
               <Link href="/personalakten">{de.nav.personnel}</Link>
             ) : null}
+            <Link href="/kanaele">{de.channel.heading}</Link>
+            <Link href="/einstellungen">{de.notify.heading}</Link>
             {user.permissions.isAdmin || user.permissions.permissions.has('roles.manage') ? (
               <>
                 <Link href="/admin/rollen">{de.nav.admin}</Link>

web/app/(app)/personalakten/[id]/Assignments.tsx

@@ -1,10 +1,10 @@
 'use client'
 
 import { useState, useTransition } from 'react'
-import { participantText } from '@/lib/i18n/cases'
-import { commonText } from '@/lib/i18n/common'
 import { assignmentText } from '@/lib/i18n/people'
+import { participantText } from '@/lib/i18n/cases'
 import { ASSIGNMENT_ROLES } from '@/lib/personnel/terms'
+import { AddPanel, PanelSelect } from '@/components/AddPanel'
 import { addAssignmentAction, removeAssignmentAction } from '../actions'
 
 type Zuordnung = {
@@ -30,10 +30,9 @@ export function Assignments({
   members: { id: string; displayName: string }[]
   canEdit: boolean
 }) {
-  const [open, setOpen] = useState(false)
   const [role, setRole] = useState<string>('HANDLER')
   const [userId, setUserId] = useState('')
-  const [error, setError] = useState<string | null>(null)
+  const [fehler, setFehler] = useState<string | null>(null)
   const [pending, startTransition] = useTransition()
 
   return (
@@ -57,11 +56,11 @@ export function Assignments({
                   disabled={pending}
                   onClick={() =>
                     startTransition(async () => {
-                      const result = await removeAssignmentAction({
+                      const ergebnis = await removeAssignmentAction({
                         personnelFileId,
                         assignmentId: zuordnung.id,
                       })
-                      if (!result.ok) setError(result.error)
+                      if (!ergebnis.ok) setFehler(ergebnis.error)
                     })
                   }
                   className="font-condensed text-2xs text-text-dim"
@@ -74,77 +73,35 @@ export function Assignments({
         </ul>
       )}
 
-      {error ? <p className="mt-2 font-condensed text-2xs text-stamp-4">{error}</p> : null}
+      {fehler ? <p className="mt-2 font-condensed text-2xs text-stamp-4">{fehler}</p> : null}
 
       {canEdit ? (
-        open ? (
-          <div className="mt-4 border border-line p-3">
-            <p className="max-w-(--container-measure) text-2xs text-text-dim">
-              {assignmentText.hint}
-            </p>
-            <div className="mt-3 flex flex-wrap items-center gap-2">
-              <select
-                value={role}
-                onChange={(event) => setRole(event.target.value)}
-                aria-label={participantText.role}
-                className="border border-line bg-raised px-2 py-1 text-2xs"
-              >
-                {ASSIGNMENT_ROLES.map((value) => (
-                  <option key={value} value={value}>
-                    {assignmentText.roles[value] ?? value}
-                  </option>
-                ))}
-              </select>
-              <select
-                value={userId}
-                onChange={(event) => setUserId(event.target.value)}
-                aria-label={participantText.pickUser}
-                className="border border-line bg-raised px-2 py-1 text-2xs"
-              >
-                <option value="">—</option>
-                {members.map((member) => (
-                  <option key={member.id} value={member.id}>
-                    {member.displayName}
-                  </option>
-                ))}
-              </select>
-              <button
-                type="button"
-                disabled={pending || !userId}
-                onClick={() =>
-                  startTransition(async () => {
-                    setError(null)
-                    const result = await addAssignmentAction({ personnelFileId, userId, role })
-                    if (result.ok) {
-                      setUserId('')
-                      setOpen(false)
-                    } else {
-                      setError(result.error)
-                    }
-                  })
-                }
-                className="border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent disabled:text-text-dim"
-              >
-                {assignmentText.add}
-              </button>
-              <button
-                type="button"
-                onClick={() => setOpen(false)}
-                className="font-condensed text-2xs text-text-dim"
-              >
-                {commonText.cancel}
-              </button>
-            </div>
-          </div>
-        ) : (
-          <button
-            type="button"
-            onClick={() => setOpen(true)}
-            className="mt-4 border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent"
-          >
-            {assignmentText.add}
-          </button>
-        )
+        <AddPanel
+          label={assignmentText.add}
+          hint={assignmentText.hint}
+          disabled={!userId}
+          onSubmit={async () => {
+            const ergebnis = await addAssignmentAction({ personnelFileId, userId, role })
+            if (ergebnis.ok) setUserId('')
+            return ergebnis
+          }}
+        >
+          <PanelSelect value={role} onChange={setRole} label={participantText.role}>
+            {ASSIGNMENT_ROLES.map((value) => (
+              <option key={value} value={value}>
+                {assignmentText.roles[value] ?? value}
+              </option>
+            ))}
+          </PanelSelect>
+          <PanelSelect value={userId} onChange={setUserId} label={participantText.pickUser}>
+            <option value="">—</option>
+            {members.map((member) => (
+              <option key={member.id} value={member.id}>
+                {member.displayName}
+              </option>
+            ))}
+          </PanelSelect>
+        </AddPanel>
       ) : null}
     </div>
   )

web/app/(app)/personalakten/[id]/LinkCase.tsx

@@ -1,10 +1,10 @@
 'use client'
 
-import { useState, useTransition } from 'react'
+import { useState } from 'react'
 import { linkText, participantText } from '@/lib/i18n/cases'
-import { commonText } from '@/lib/i18n/common'
 import { personnelText } from '@/lib/i18n/people'
 import { PARTICIPANT_ROLES } from '@/lib/cases/terms'
+import { AddPanel, PanelSelect } from '@/components/AddPanel'
 import { linkCaseToPersonAction } from '../actions'
 
 /**
@@ -16,81 +16,34 @@ import { linkCaseToPersonAction } from '../actions'
  * sichtbaren Fälle wäre auf einer Personalakte am falschen Ort.
  */
 export function LinkCase({ personnelFileId }: { personnelFileId: string }) {
-  const [open, setOpen] = useState(false)
   const [caseNumber, setCaseNumber] = useState('')
   const [role, setRole] = useState<string>('SUBJECT')
-  const [error, setError] = useState<string | null>(null)
-  const [pending, startTransition] = useTransition()
-
-  if (!open) {
-    return (
-      <button
-        type="button"
-        onClick={() => setOpen(true)}
-        className="mt-4 border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent"
-      >
-        {personnelText.linkCase}
-      </button>
-    )
-  }
 
   return (
-    <div className="mt-4 border border-line p-3">
-      <p className="max-w-(--container-measure) text-2xs text-text-dim">
-        {personnelText.linkCaseHint}
-      </p>
-      <div className="mt-3 flex flex-wrap items-center gap-2">
-        <select
-          value={role}
-          onChange={(event) => setRole(event.target.value)}
-          aria-label={participantText.role}
-          className="border border-line bg-raised px-2 py-1 text-2xs"
-        >
-          {PARTICIPANT_ROLES.map((value) => (
-            <option key={value} value={value}>
-              {participantText.roles[value] ?? value}
-            </option>
-          ))}
-        </select>
-        <input
-          value={caseNumber}
-          onChange={(event) => setCaseNumber(event.target.value)}
-          placeholder={linkText.target}
-          aria-label={linkText.target}
-          className="border border-line bg-raised px-2 py-1 font-mono text-2xs"
-        />
-        <button
-          type="button"
-          disabled={pending || caseNumber.trim() === ''}
-          onClick={() =>
-            startTransition(async () => {
-              setError(null)
-              const result = await linkCaseToPersonAction({
-                personnelFileId,
-                caseNumber,
-                role,
-              })
-              if (result.ok) {
-                setCaseNumber('')
-                setOpen(false)
-              } else {
-                setError(result.error)
-              }
-            })
-          }
-          className="border border-line bg-raised px-3 py-1 font-condensed text-2xs text-accent disabled:text-text-dim"
-        >
-          {personnelText.linkCase}
-        </button>
-        <button
-          type="button"
-          onClick={() => setOpen(false)}
-          className="font-condensed text-2xs text-text-dim"
-        >
-          {commonText.cancel}
-        </button>
-      </div>
-      {error ? <p className="mt-2 font-condensed text-2xs text-stamp-4">{error}</p> : null}
-    </div>
+    <AddPanel
+      label={personnelText.linkCase}
+      hint={personnelText.linkCaseHint}
+      disabled={caseNumber.trim() === ''}
+      onSubmit={async () => {
+        const ergebnis = await linkCaseToPersonAction({ personnelFileId, caseNumber, role })
+        if (ergebnis.ok) setCaseNumber('')
+        return ergebnis
+      }}
+    >
+      <PanelSelect value={role} onChange={setRole} label={participantText.role}>
+        {PARTICIPANT_ROLES.map((value) => (
+          <option key={value} value={value}>
+            {participantText.roles[value] ?? value}
+          </option>
+        ))}
+      </PanelSelect>
+      <input
+        value={caseNumber}
+        onChange={(event) => setCaseNumber(event.target.value)}
+        placeholder={linkText.target}
+        aria-label={linkText.target}
+        className="border border-line bg-raised px-2 py-1 font-mono text-2xs"
+      />
+    </AddPanel>
   )
 }