Add repetition_date support for tasks (v3.3.0)

- Add repetition_date field to tasks table (migration 018)
- Support pattern-based repetition: day of week, day of month, specific date
- Add 'Через'/'Каждое' mode selector in task form
- Auto-calculate next_show_at from repetition_date on create/complete
- Show calculated next date in postpone dialog for repetition_date tasks
- Update version to 3.3.0

play-life-web/package.json

@@ -1,6 +1,6 @@
 {
   "name": "play-life-web",
-  "version": "3.2.0",
+  "version": "3.3.0",
   "type": "module",
   "scripts": {
     "dev": "vite",