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/help/HelpView.tsx

@@ -558,6 +558,9 @@ export const HelpView: React.FC<HelpViewProps> = ({ onBack }) => {
               <li>
                 <strong className="text-main">Zuweisen:</strong> In geteilten Aufgabenlisten weist du eine Aufgabe einer oder mehreren Personen mit Zugriff zu (Namen tippen, Enter). Die Zugewiesenen erscheinen als kleine Profilbilder an der Aufgabe; wer den Zugriff auf die Liste verliert, wird automatisch entfernt.
               </li>
+              <li>
+                <strong className="text-main">Wiederkehrende Aufgaben:</strong> Im Detail-Fenster eine Wiederholung wählen (täglich bis jährlich). Beim Abhaken entsteht automatisch die nächste Aufgabe mit fortgeschriebenem Datum; erkennbar am 🔁-Symbol.
+              </li>
               <li>
                 <strong className="text-main">Automatische Alarme:</strong> Ist ein Fälligkeitsdatum erreicht, kann MindSift dich automatisch per <strong className="text-main">E-Mail</strong>, <strong className="text-main">Discord-Webhook</strong> oder individuellem HTTP-Webhook benachrichtigen. Konfigurierbar in deinen Benutzereinstellungen.
               </li>

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 */}

frontend/src/features/triage/TasksView.tsx

@@ -25,8 +25,9 @@ import {
   Folder,
   Filter,
   Webhook,
+  Repeat,
 } from 'lucide-react';
-import { TaskList, Thought, SubTask, Team, User, TaskListShare, TaskListMember, KanbanColumn, PriorityLevel } from '../../lib/types';
+import { TaskList, Thought, SubTask, Team, User, TaskListShare, TaskListMember, KanbanColumn, PriorityLevel, Recurrence, RECURRENCE_LABELS } from '../../lib/types';
 import { api, triggerHaptic } from '../../lib/api';
 import { UnifiedShareModal } from '../../components/UnifiedShareModal';
 import { TaskDetailModal } from './TaskDetailModal';
@@ -504,6 +505,15 @@ export const TasksView: React.FC<TasksViewProps> = ({
     await api.updateThought(task.id, { notes: newNotes });
   };
 
+  const handleUpdateTaskRecurrence = async (task: Thought, recurrence: Recurrence) => {
+    setTasks((prev) => prev.map((t) => (t.id === task.id ? { ...t, recurrence } : t)));
+    try {
+      await api.updateThought(task.id, { recurrence });
+    } catch {
+      setTasks((prev) => prev.map((t) => (t.id === task.id ? { ...t, recurrence: task.recurrence } : t)));
+    }
+  };
+
   const handleUpdateTaskAssignees = async (task: Thought, assignees: string[]) => {
     triggerHaptic(10);
     setTasks((prev) => prev.map((t) => (t.id === task.id ? { ...t, assignees } : t)));
@@ -1306,6 +1316,11 @@ export const TasksView: React.FC<TasksViewProps> = ({
                   <span>{task.dueDate}</span>
                 </span>
               )}
+              {task.recurrence && (
+                <span className="inline-flex items-center text-muted" title={`Wiederholt sich ${RECURRENCE_LABELS[task.recurrence]}`}>
+                  <Repeat className="w-3 h-3" />
+                </span>
+              )}
 
               {/* Hashtag badges */}
               {task.tags?.map((tag) => (
@@ -2131,6 +2146,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
         onUpdateStatus={handleSetKanbanStatus}
         onUpdatePriority={handleSetPriority}
         onUpdateDueDate={handleUpdateTaskDueDate}
+        onUpdateRecurrence={handleUpdateTaskRecurrence}
         onUpdateTaskList={handleUpdateTaskTaskList}
         onUpdateNotes={handleUpdateTaskNotes}
         onUpdateTags={handleUpdateTaskTags}
@@ -2324,6 +2340,11 @@ export const TasksView: React.FC<TasksViewProps> = ({
                               <span>{task.dueDate}</span>
                             </span>
                           )}
+                          {task.recurrence && (
+                            <span className="inline-flex items-center text-muted" title={`Wiederholt sich ${RECURRENCE_LABELS[task.recurrence]}`}>
+                              <Repeat className="w-2.5 h-2.5" />
+                            </span>
+                          )}
                           {task.tags?.map((tag) => (
                             <button
                               key={tag}

frontend/src/lib/api.ts

@@ -390,6 +390,7 @@ export const api = {
       subtasks?: SubTask[];
       tags?: string[];
       assignees?: string[];
+      recurrence?: string;
     }
   ): Promise<Thought> {
     return request<Thought>(`/api/v1/thoughts/${thoughtId}`, {

frontend/src/lib/types.ts

@@ -57,6 +57,16 @@ export interface SubTask {
   createdAt?: string;
 }
 
+// Repeat rule of a task: completing it creates the next one (due date one interval later)
+export type Recurrence = '' | 'daily' | 'weekly' | 'monthly' | 'yearly';
+
+export const RECURRENCE_LABELS: Record<Exclude<Recurrence, ''>, string> = {
+  daily: 'täglich',
+  weekly: 'wöchentlich',
+  monthly: 'monatlich',
+  yearly: 'jährlich',
+};
+
 export interface Thought {
   id: string;
   userId: string;
@@ -76,6 +86,7 @@ export interface Thought {
   notes?: string;
   subtasks?: SubTask[];
   assignees?: string[]; // user IDs, only people with access to the task list
+  recurrence?: Recurrence;
   alarmSent?: boolean;
   sortOrder?: number;
   createdAt: string;