docs(book-matching,collections): Beam batch 10 — 15 endpoints

WO3 sync internals resolved: the book-matching docs ARE the sync surface
(books/query, link-book, bulk/auto-link, unlinked-books, suggestions,
file-alias CRUD) + collections rule/test/bulk-assign/shelf-mapping
surface.

Dedupe resolved (Claude call): search_books.md declared
GET /api/books/match but its BODY documents POST /api/sync/books/query —
both routes exist and are distinct (query-param device protocol vs JSON
body plugin protocol). Repointed search_books.md frontmatter to the POST
route; get_book_matches.md keeps the GET.

Claude registry: 15 entries (one pre-existing link-book entry deduped).
Drift fixed by gate: auto-link request {confidence_threshold, limit} not
{device_id, threshold}; bulk-link link objects {unlinked_book_id,
media_item_id, confidence_score} not {device_id, book_id, ...};
responses {results,total,successful,failed}/{auto_linked,results}; added
missing example-responses (bare delete, remove-rule is_smart-after
semantics, bulk-assign per-book results). make test 9/9.

docs/developer/api/book-matching/auto_link_books.md

@@ -1,3 +1,11 @@
+---
+method: POST
+path: /api/sync/auto-link-books
+auth: jwt
+area: book-matching
+---
+<!-- source: internal/handlers/book_matching.go:316 Handler.AutoLinkBooks -->
+
 # Auto Link Books
 
 Automatically link books to media items based on matching metadata.
@@ -15,27 +23,19 @@ Automatically link books to media items based on matching metadata.
 
 ### Example Request
 
-```json
+```json example-request
 {
-  "device_id": "550e8400-e29b-41d4-a716-446655440000",
-  "threshold": 0.8
+  "confidence_threshold": 0.8,
+  "limit": 100
 }
 ```
 
 ## Response (200 OK)
 
-```json
+```json example-response
 {
-  "message": "Auto-link completed",
-  "linked_count": 15,
-  "unmatched_count": 5,
-  "links": [
-    {
-      "book_id": "book-123",
-      "media_item_id": "uuid",
-      "confidence": 0.95
-    }
-  ]
+  "auto_linked": null,
+  "results": null
 }
 ```