refactor(media): unify use-case I/O schemas + presenter + feature error map

Per Plan 9 (spec R1-R28):
- Use cases: input + output schemas (getMedia, listMedia); deleteMedia
  has input schema only (void output, R12 — no presenter).
- Controllers: unknown input + identity presenter on getMedia/listMedia;
  Promise<void> on deleteMedia.
- New integrations/api/procedures.ts with mediaProcedure
  ([InputParseError → BAD_REQUEST], [MediaNotFoundError → NOT_FOUND]).
- Router uses mediaProcedure + .input(xInputSchema).
- src/index.ts exports schemas + types; src/ui/index.ts placeholder
  (media has no queries today); package.json adds ./ui subpath.
- R25 + R26 tests added.

Refactor log: §1, §2, §3.1, §3.2, §3.3, §5.1, §5.2, §6.1, §6.2
Spec: R1–R6, R8–R15, R18–R20, R22–R26

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/media/src/ui/index.ts

@@ -0,0 +1,4 @@
+// Media has no React Query option builders today. This file is the
+// public UI surface for future components and queries — extend rather
+// than re-add to root index.ts.
+export {};