feat(notifications): add channel routing matrix, daily summary, and task watch button

frontend/src/features/triage/TaskDetailModal.tsx

@@ -15,11 +15,13 @@ import {
   Lock,
   UserPlus,
   Repeat,
+  Eye,
+  EyeOff,
 } from 'lucide-react';
 import { Thought, TaskList, TaskListMember, KanbanColumn, User, Recurrence } from '../../lib/types';
 import { UserAvatar } from '../../components/UserAvatar';
 import { UserAutocomplete } from '../UserAutocomplete';
-import { triggerHaptic } from '../../lib/api';
+import { api, triggerHaptic } from '../../lib/api';
 import { MarkdownViewer } from '../../lib/markdown';
 import { addDays, joinDue, splitDue } from '../../lib/due';
 
@@ -90,13 +92,32 @@ const TaskDetailModalContent: React.FC<TaskDetailModalProps & { task: Thought }>
 
   const [newSubtaskTitle, setNewSubtaskTitle] = useState('');
   const [newTagDraft, setNewTagDraft] = useState('');
+  const [isWatching, setIsWatching] = useState<boolean>(Boolean(task.isWatching));
+  const [watchBusy, setWatchBusy] = useState(false);
 
   useEffect(() => {
     setTitleDraft(task.content);
     setNotesDraft(task.notes || '');
     setIsEditingTitle(false);
     setIsEditingNotes(false);
-  }, [task.id]);
+    setIsWatching(Boolean(task.isWatching));
+  }, [task.id, task.isWatching]);
+
+  const handleToggleWatch = async () => {
+    if (watchBusy) return;
+    setWatchBusy(true);
+    try {
+      const res = isWatching ? await api.unwatchTask(task.id) : await api.watchTask(task.id);
+      const next = Boolean(res.watching);
+      setIsWatching(next);
+      task.isWatching = next;
+      triggerHaptic(10);
+    } catch {
+      // ignore
+    } finally {
+      setWatchBusy(false);
+    }
+  };
 
   // Handle escape key to close
   useEffect(() => {
@@ -226,6 +247,27 @@ const TaskDetailModalContent: React.FC<TaskDetailModalProps & { task: Thought }>
           </div>
 
           <div className="flex items-center gap-1.5">
+            <button
+              type="button"
+              onClick={handleToggleWatch}
+              disabled={watchBusy}
+              title={isWatching ? 'Nicht mehr beobachten' : 'Beobachten'}
+              className={`btn-action min-h-[44px] sm:min-h-0 h-11 sm:h-7 px-2.5 sm:px-2 text-xs flex items-center gap-1.5 ${
+                isWatching ? 'border-accent text-accent' : ''
+              }`}
+            >
+              {isWatching ? (
+                <>
+                  <EyeOff className="w-4 h-4 sm:w-3.5 sm:h-3.5 text-accent" />
+                  <span>Nicht mehr beobachten</span>
+                </>
+              ) : (
+                <>
+                  <Eye className="w-4 h-4 sm:w-3.5 sm:h-3.5" />
+                  <span>Beobachten</span>
+                </>
+              )}
+            </button>
             {(task.convertedType === 'document_block' || task.docId) ? (
               <button
                 type="button"

frontend/src/features/triage/__tests__/TaskDetailModal.test.tsx

@@ -1,6 +1,7 @@
 import { describe, it, expect, vi } from 'vitest';
-import { render, screen, fireEvent } from '@testing-library/react';
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
 import { TaskDetailModal } from '../TaskDetailModal';
+import { api } from '../../../lib/api';
 import { Thought } from '../../../lib/types';
 
 const task: Thought = {
@@ -67,4 +68,20 @@ describe('TaskDetailModal', () => {
     expect(screen.getByText('Aufgabe ansehen')).toBeTruthy();
     expect((screen.getByLabelText('Fälligkeitsdatum') as HTMLInputElement).closest('fieldset')?.disabled).toBe(true);
   });
+
+  it('toggles watching a task via POST and DELETE /tasks/{id}/watch', async () => {
+    const watchSpy = vi.spyOn(api, 'watchTask').mockResolvedValue({ watching: true });
+    const unwatchSpy = vi.spyOn(api, 'unwatchTask').mockResolvedValue({ watching: false });
+
+    render(<TaskDetailModal {...props({ task: { ...task, isWatching: false } })} />);
+    const btn = screen.getByRole('button', { name: 'Beobachten' });
+    fireEvent.click(btn);
+
+    await waitFor(() => expect(watchSpy).toHaveBeenCalledWith('th_1'));
+    expect(screen.getByRole('button', { name: 'Nicht mehr beobachten' })).toBeTruthy();
+
+    fireEvent.click(screen.getByRole('button', { name: 'Nicht mehr beobachten' }));
+    await waitFor(() => expect(unwatchSpy).toHaveBeenCalledWith('th_1'));
+    expect(screen.getByRole('button', { name: 'Beobachten' })).toBeTruthy();
+  });
 });