feat(tasks): support reminder write via dot-notation (v1.2.0)

- Add reminder_unit, reminder_value to create_task
- Add reminder_unit, reminder_value, clear_reminder to update_task
- Wire format verified: reminder.reminderUnit / .reminderValue /
  .reminderType (SNOOZE=active, NONE=clear) / .localId (optional)
- Valid units: MINUTE, HOUR, DAY (WEEK rejected by enum decoder)
- Clear requires full inactive block; partial updates reject with
  "task reminder invalid"
- Flat top-level keys, JSON string and bracket notation are silently
  ignored by the server — confirmed via isolated fuzz per variant
- Update SPEC.md, CLAUDE.md, README.md, CHANGELOG.md
- Remove outdated "not supported" warning in update_task docstring

README.md

@@ -28,8 +28,8 @@ MCP server for [Family Wall](https://www.familywall.com) — manage your family'
 | `delete_list` 🔒 | Permanently delete a list and all its tasks (system lists protected) |
 | `create_category` 🔒 | Create a custom category (with optional icon) |
 | `delete_category` 🔒 | Delete a custom category (system categories protected) |
-| `create_task` 🔒 | Create a task (supports category, due date, assignees; use `"Äpfel (5x)"` for quantities) |
-| `update_task` 🔒 | Update text, category, due date, assignees, or move to a different list |
+| `create_task` 🔒 | Create a task (category, due date, assignees, reminder; use `"Äpfel (5x)"` for quantities) |
+| `update_task` 🔒 | Update text, category, due date, assignees, recurrency, reminder, or move to a different list |
 | `toggle_task` 🔒 | Mark a task complete or reopen it |
 | `delete_task` 🔒 | Permanently delete a task |
 | `clear_list` 🔒 | Bulk-delete all tasks in a list (optional `only_open=True` keeps completed tasks) |