feat(matrix): add Matrix Todo Bot service

GDPR-compliant task management bot for Matrix with:
- Task CRUD: !add, !list, !done, !delete
- Priority support: !p1 to !p4
- Date shortcuts: @heute, @morgen, @übermorgen
- Project tags: #projektname
- Natural language keywords: hilfe, zeige aufgaben, heute
- Welcome messages and auto-pin help on room join
- Per-user task isolation via Matrix user ID
- Local JSON storage

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.macmini.yml

@@ -975,6 +975,35 @@ services:
       retries: 3
       start_period: 40s
 
+  # ============================================
+  # Matrix Todo Bot (GDPR-compliant Task Management)
+  # ============================================
+
+  matrix-todo-bot:
+    image: matrix-todo-bot:latest
+    container_name: manacore-matrix-todo-bot
+    restart: always
+    depends_on:
+      synapse:
+        condition: service_healthy
+    environment:
+      NODE_ENV: production
+      PORT: 3314
+      TZ: Europe/Berlin
+      MATRIX_HOMESERVER_URL: http://synapse:8008
+      MATRIX_ACCESS_TOKEN: ${MATRIX_TODO_BOT_TOKEN}
+      MATRIX_ALLOWED_ROOMS: ${MATRIX_TODO_BOT_ROOMS:-}
+    volumes:
+      - matrix_todo_bot_data:/app/data
+    ports:
+      - "3314:3314"
+    healthcheck:
+      test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://127.0.0.1:3314/health"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 40s
+
   # ============================================
   # Auto-Update (Watchtower)
   # ============================================
@@ -1023,3 +1052,5 @@ volumes:
     name: manacore-matrix-stats-bot
   matrix_project_doc_bot_data:
     name: manacore-matrix-project-doc-bot
+  matrix_todo_bot_data:
+    name: manacore-matrix-todo-bot