Calendars as entities, uniform widget contract, multi-dashboard tasks

Architecture refinements before module work begins:

- Calendars become first-class entities (mirror of lists). Each
  calendar has its own visibility (private | household) and is
  independently shareable. Updated CLAUDE.md data model and task 10.

- Drop the singleton/parameterized split for dashboard widgets. Every
  widget declares a configSchema + defaultConfig + resolveConfigOptions
  and every placement is an independent instance — same widgetId can
  appear multiple times on one dashboard pointed at different things.
  Updated task 04 contract; tasks 11/12 widget sections aligned.

- Add tasks 25 (multiple dashboards per user) and 26 (customizable
  layout + widget configuration). Replaces the previously-considered
  three-task plan with a cleaner two-task split that the uniform
  contract enables. Phase 3 index updated; STATUS records the rationale.

- Task 20 reframed as a single-dashboard MVP that exercises the new
  contract end-to-end before the customization layer lands.

docs/tasks/12-notes-module.md

@@ -14,8 +14,9 @@ Lightweight shared notes with optional reminders.
 - `/notes` index: pinned first, then by updated_at desc.
 - `/notes/[id]` editor — minimal markdown (use `@uiw/react-md-editor` or similar; live preview optional).
 - `remind_at` writes a row to `reminders` (table comes from `_core`; reminder firing comes from task 41).
-- Manifest: shareable, remindable, searchable (title + body).
-- Dashboard widget: pinned notes.
+- Manifest:
+  - Entity `notes.note` — shareable, remindable, searchable (title + body).
+  - Widget (uniform contract per task 04): **`notes.filtered`** — `config: { filter: "pinned" | "all"; limit?: number }`. Default `{ filter: "pinned", limit: 10 }`. `resolveConfigOptions` returns nothing yet (placeholder for future tag filtering).
 
 ## Out of scope