feat(tasks): repeating tasks (daily, weekly, monthly, yearly)

- recurrence on tasks, set in the detail dialog; 🔁 on rows and Kanban cards
- Completing a repeating task (detail, list, Kanban drag to done, note
  checkbox) creates the next one: title, tags, priority, notes, list,
  assignees and rule copied, subtasks reset, first open column, due date
  one interval later (month end clamped); pushed live as TASK_CREATED
- Each task spawns at most once (re-open + complete makes no duplicate)
- Export/import keep the rule (Obsidian Tasks "🔁 every week", JSON field)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/triage/TaskDetailModal.tsx

@@ -17,8 +17,9 @@ import {
   Webhook,
   Lock,
   UserPlus,
+  Repeat,
 } from 'lucide-react';
-import { Thought, SubTask, TaskList, TaskListMember, KanbanColumn, User } from '../../lib/types';
+import { Thought, SubTask, TaskList, TaskListMember, KanbanColumn, User, Recurrence } from '../../lib/types';
 import { UserAvatar } from '../../components/UserAvatar';
 import { UserAutocomplete } from '../UserAutocomplete';
 import { triggerHaptic } from '../../lib/api';
@@ -34,6 +35,7 @@ interface TaskDetailModalProps {
   onUpdateStatus: (task: Thought, newStatus: string) => Promise<void>;
   onUpdatePriority: (task: Thought, newPriority: string) => Promise<void>;
   onUpdateDueDate: (task: Thought, newDueDate: string) => Promise<void>;
+  onUpdateRecurrence?: (task: Thought, recurrence: Recurrence) => Promise<void>;
   onUpdateTaskList: (task: Thought, newListId: string) => Promise<void>;
   onUpdateNotes: (task: Thought, newNotes: string) => Promise<void>;
   onUpdateTags?: (task: Thought, newTags: string[]) => Promise<void>;
@@ -58,6 +60,7 @@ export const TaskDetailModal: React.FC<TaskDetailModalProps> = ({
   onUpdateStatus,
   onUpdatePriority,
   onUpdateDueDate,
+  onUpdateRecurrence,
   onUpdateTaskList,
   onUpdateNotes,
   onUpdateTags,
@@ -509,6 +512,32 @@ export const TaskDetailModal: React.FC<TaskDetailModalProps> = ({
                   +1 Woche
                 </button>
               </div>
+              {onUpdateRecurrence && (
+                <div className="pt-1">
+                  <label className="flex items-center gap-1 text-[11px] text-muted mb-1">
+                    <Repeat className="w-3 h-3 text-accent" />
+                    <span>Wiederholung</span>
+                  </label>
+                  <select
+                    value={task.recurrence || ''}
+                    disabled={readOnly}
+                    onChange={(e) => onUpdateRecurrence(task, e.target.value as Recurrence)}
+                    className="w-full h-11 sm:h-8 input-field px-2 text-base sm:text-xs bg-panel"
+                  >
+                    <option value="">Keine Wiederholung</option>
+                    <option value="daily">🔁 Täglich</option>
+                    <option value="weekly">🔁 Wöchentlich</option>
+                    <option value="monthly">🔁 Monatlich</option>
+                    <option value="yearly">🔁 Jährlich</option>
+                  </select>
+                  {task.recurrence && (
+                    <p className="text-[10px] text-faint mt-1">
+                      Beim Erledigen entsteht automatisch die nächste Aufgabe, fällig{' '}
+                      {task.dueDate ? 'ein Intervall nach diesem Datum' : 'ein Intervall nach dem Erledigen'}.
+                    </p>
+                  )}
+                </div>
+              )}
             </div>
 
             {/* Task List assignment */}