feat(web): book reviews — markdown, sibling of ratings, full API + page surface

media_reviews table mirrors media_ratings' shape (unique per user+item,
cascade deletes, updated_at for LWW) but standalone: a review without a
rating must work. Body is RAW MARKDOWN — storage and every payload carry
the source; rendering happens only at display sites (same doctrine as
notes, same sanitization pipeline: markdown-it + DOMPurify).

API: GET/PUT/DELETE /api/media-items/:id/review (PUT upserts; an empty
body deletes — clearing via an editor is a delete, not an empty row).
Book-detail page payload now carries the review beside the rating.

Page: the review renders above the synopsis as a scrolling card (same
max-height box as the summary), hydrated client-side through
renderNoteHtml; 'Write review'/'Edit review' sits next to the rating
stars and opens a raw-markdown editor dialog (save / delete / cancel).

sqlc regenerated; schema applied to the dev DB. Live-verified: upsert,
get, empty-delete, page markup, and the app round-trip against the dev
server.

internal/database/db.go

@@ -1,6 +1,6 @@
 // Code generated by sqlc. DO NOT EDIT.
 // versions:
-//   sqlc v1.31.0
+//   sqlc v1.31.1
 
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