Initial scaffold: tooling, plan, task briefs

- pnpm 10 workspace + TypeScript strict + ESLint flat + Prettier
- CLAUDE.md as canonical brief
- docs/tasks/ — 22 task briefs broken out by phase for sub-sessions
- docs/decisions/ — ADR scaffold

Implements task 01 (repo-init).

docs/tasks/31-share-viewer.md

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+# 31 — Public share viewer (`/s/<token>`)
+
+## Goal
+
+Unauthenticated route that resolves a share token and renders the entity using its manifest's `loadForShare` adapter.
+
+## Depends on
+
+- 30
+
+## Scope
+
+- `/s/[token]/page.tsx` — server component. Calls `resolveShareToken`. If valid, calls the entity's `loadForShare(id)` and renders a per-type viewer component (each module exports a `<SharedView />`).
+- If the token grants write capability, render an editable view (initially only relevant for lists — recipient can check items off).
+- Friendly error page for invalid/expired/revoked tokens.
+- Add `noindex` headers on the route.
+
+## Out of scope
+
+- Auth on the share page (deliberately public; security is the unguessable token).
+- Comments / reactions from anonymous viewers.
+
+## Acceptance criteria
+
+- [ ] Calendar event share renders title/time/location/notes — read-only.
+- [ ] Shopping list share with `write: true` lets a recipient toggle items; toggles round-trip back into the household (with `actor_id = null` in activity log, action `share.toggle`).
+- [ ] Middleware does not gate `/s/*`.