feat: cases (reports, rating reviews, removal and deletion requests, appeals) and notifications

Cases are one queue for what someone has to decide, each with a thread (internal notes for those deciding), an
assignee and a decision. Reports about a product go to the teams of the catalogs hosting it and to moderators, and
only the reporter and moderators know who reported. A creator lowering a rating opens a rating review; a catalog's
owner asking to delete it opens a deletion request; a catalog's team can ask for a product's removal everywhere; the
person an action affected can appeal it once, decided by another moderator (an admin may decide their own, flagged).
Resolving carries the case out: the rating is lowered, the product removed, the catalog deleted.

Notifications reach people on the website (a bell with the unread count) and their proxies (realtime): moderators'
edits to their products, removals and restores, decisions and replies on their cases, membership decisions.

Also: moderators can restore a removed product, and a product's creator and moderators can see it when it's adult
without an adult account (getting and wearing it still need one).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/design.md

@@ -477,7 +477,8 @@ Phases for products, catalogs and imports (products.md, console.md, imports.md):
    within its parent's top-level category; IMVU's own category tree (if it has a public one) would replace those
    (to look into with the importer spike).
 3. Cases (reports, appeals, reviews), file blocks and the catalogs' changes feed; notifications; API tokens;
-   two-factor sign-in for sensitive permissions.
+   two-factor sign-in for sensitive permissions. Cases and notifications **done** (2026-11-05), without email, canned
+   reasons, moderator notes or second approval; file blocks, API tokens and two-factor sign-in next.
 4. Imports: grants, recorded grants, requests, unclaimed creators, the job queue, `t5de-importer` (after its spike).
 5. Charts and stats; mirroring between catalogs.