feat(notifications): add channel routing matrix, daily summary, and task watch 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();
+  });
 });