# 30 — Share-link service

## Goal

A generic service that issues temporary, scoped, revocable share tokens for any registered entity.

## Depends on

- 04 (registry), 07 (household)

## Scope

- Schema: `share_links` (`id`, `household_id`, `entity_type`, `entity_id`, `token` unique, `capabilities` jsonb (e.g. `{ read: true, write: false }`), `created_by`, `expires_at` nullable, `revoked_at` nullable, `created_at`).
- `_core/share.ts`:
  - `createShareLink(entityType, entityId, opts)` → `{ url, token, expiresAt }`.
  - `resolveShareToken(token)` → `{ entityType, entityId, capabilities } | null` (rejects expired/revoked).
  - `revokeShareLink(id)`.
- Verifies the entity type is registered and shareable per its manifest's `share` capability declaration.
- Token format: 32-byte URL-safe base64. Stored hashed (sha-256) — only the URL contains the raw token.

## Out of scope

- The viewer page (task 31).
- Rate limiting (task 61).
- Per-recipient access logs.

## Acceptance criteria

- [ ] Creating a link for an entity type with `share: undefined` throws.
- [ ] Tokens are stored hashed; raw token only returned at creation.
- [ ] Expired/revoked tokens return null.
- [ ] `/settings` shows active share links per entity with revoke buttons.