User-owned named lists of mangas with an add-to-collection modal on
the manga page and dedicated /collections and /collections/:id pages.
- Schema (0010): `collections` (per-user case-insensitive name
uniqueness) + `collection_mangas` join with cascade FKs.
- Endpoints: full CRUD on `/v1/collections`, idempotent add/remove
for `/v1/collections/:id/mangas`, and `/v1/mangas/:id/my-collections`
for the modal's pre-checked state. Owner-mismatch surfaces as 404
(not 403) so the API doesn't disclose collection existence to
non-owners; the frontend funnels 401 to /login. Three-state PATCH
via a new shared `domain::patch::Patch<T>` lets clients distinguish
"leave alone", "clear", and "set" for description.
- Frontend: reusable `Modal` component (focus trap, opt-in
backdrop close, ESC) and `AddToCollectionModal` with optimistic
toggling that's race-safe under fast clicks. /collections page
renders cover-collage cards; /collections/:id is editable with
per-card remove. Top nav gets a Collections link.
155 backend tests (incl. 21 collection tests covering ownership,
idempotence, sample-cover enrichment, three-state PATCH, FK race);
88 frontend tests; svelte-check clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
