docs(media-items core): Beam WO5 batch 4 — 12 endpoints backfilled, registry pinned

Beam backfilled list/get/create/update/delete media-item, search, ratings
CRUD, progress GET/PUT. Beam correctly identified create/update/delete as
jwt+admin (admin group in the router — verified).

Claude registry: 12 entries. Notable pins:
- get_media_item: hand-built ~44-key map pinned verbatim from the handler
- create/update return the full database.MediaItems row (74 columns) —
  examples merged up to the real shape via gate-driven merge script
- search returns []SearchMediaItemsRow (sqlc row — Real type pinned)
- rating scale is 1-10 int (odd = half-star); GET returns {rating: null} when
  absent; update reuses the create handler (201)
- progress GET: 25 base keys + 4 CONDITIONAL position-authority keys
  (css_selector/anchor_href/char_offset/context_text — added by the handler
  for convertible formats with a valid CFI); PUT progress binds
  sync.SaveProgressRequest and returns database.ReadingProgress
- Beam's examples were missing entirely on 4 files (list/search/progress
  GET/PUT) — relabeled existing fences or inserted contract-shaped blocks

Gate-driven merge scripts (object + array variants) brought all examples to
the exact handler key sets. make test 9/9.

docs/developer/api/media-items/create_media_item.md

@@ -1,3 +1,11 @@
+---
+method: POST
+path: /api/media-items
+auth: jwt+admin
+area: media-items
+---
+<!-- source: internal/handlers/media.go:1375 MediaHandler.CreateMediaItem -->
+
 # Create Media Item
 
 Create a new media item (Admin only).
@@ -47,7 +55,7 @@ Tags and contributors are automatically normalized:
 
 ### Example Request
 
-```json
+```json example-request
 {
   "library_id": "550e8400-e29b-41d4-a716-446655440000",
   "title": "Example Book Title",
@@ -67,7 +75,7 @@ Tags and contributors are automatically normalized:
 
 ## Response (201 Created)
 
-```json
+```json example-response
 {
   "id": "550e8400-e29b-41d4-a716-446655440001",
   "library_id": "550e8400-e29b-41d4-a716-446655440000",
@@ -80,13 +88,83 @@ Tags and contributors are automatically normalized:
   "mime_type": "application/epub+zip",
   "series": "Tech Series",
   "series_number": 1,
-  "tags": ["Science-Fiction", "Technology", "ACME CORP."],
-  "tags_search": ["science fiction", "technology", "acme corp"],
+  "tags": [
+    "Science-Fiction",
+    "Technology",
+    "ACME CORP."
+  ],
+  "tags_search": [
+    "science fiction",
+    "technology",
+    "acme corp"
+  ],
   "publisher": "O'Reilly Media",
-  "contributors": ["John Smith", "ACME CORP."],
-  "contributors_search": ["john smith", "acme corp"],
+  "contributors": [
+    "John Smith",
+    "ACME CORP."
+  ],
+  "contributors_search": [
+    "john smith",
+    "acme corp"
+  ],
   "created_at": "2026-01-31T10:00:00Z",
-  "updated_at": "2026-01-31T10:00:00Z"
+  "updated_at": "2026-01-31T10:00:00Z",
+  "abridged": null,
+  "added_by_admin_id": null,
+  "age_rating": null,
+  "alternate_info": null,
+  "archived_at": null,
+  "asin": null,
+  "audio_metadata": null,
+  "authors": null,
+  "authors_search": null,
+  "chapter_count": null,
+  "chapter_metadata": null,
+  "community_rating": null,
+  "copyright_year": null,
+  "cover_image_path": null,
+  "date_published": null,
+  "edition": null,
+  "entitlement_id": null,
+  "explicit": null,
+  "file_sha256": null,
+  "format_group": null,
+  "format_mimetype": null,
+  "genre": null,
+  "goodreads_id": null,
+  "google_books_id": null,
+  "has_fixed_layout": null,
+  "hash_confidence": null,
+  "imported_at": null,
+  "imprint": null,
+  "is_black_and_white": null,
+  "is_reflowable": null,
+  "kobo_content_id": null,
+  "kobo_metadata": null,
+  "language": null,
+  "library_type_name": null,
+  "manga_type": null,
+  "metadata_notes": null,
+  "metadata_overrides": null,
+  "missing_scan_count": null,
+  "narrators": null,
+  "narrators_search": null,
+  "openlibrary_id": null,
+  "opf_identifier": null,
+  "opf_uuid": null,
+  "page_count": null,
+  "publishers": null,
+  "publishers_search": null,
+  "reading_direction": null,
+  "revision_number": null,
+  "scan_information": null,
+  "series_count": null,
+  "story_arc": null,
+  "subtitle": null,
+  "summary": null,
+  "total_characters": null,
+  "volume": null,
+  "web_url": null
 }
 ```