docs(kobo,koreader,collections): Beam WO5 batch 6 — 12 endpoints

Kobo emulation + KOReader calibre-compatible surface backfilled with
device-token auth; collections reorder + update_rule created.

Claude registry: 12 entries. kobo/koreader emulation endpoints all bind
arbitrary protocol POST bodies (markup/bookmark/gettests/sync-from-server,
koreader progress/bookmarks) — registered as AnyJSONObject, not bodyless as
first drafted. Initialization returns the library sync payload, not the init
response.

Contract correction in update_rule.md: the route is SetRuleEnabled ({enabled}
required -> {collection_id, is_smart}); Beam's draft invented rule-field
updates. Reordered response/status: {item_ids} -> {status: reordered}.

make test 9/9.

docs/developer/api/koreader/sync_bookmarks.md

@@ -1,3 +1,11 @@
+---
+method: POST
+path: /api/sync/koreader/bookmarks
+auth: device-token
+area: koreader
+---
+<!-- source: internal/handlers/koreader.go:1456 KOReaderHandler.SyncBookmarks -->
+
 # Sync Bookmarks
 
 Sync bookmarks, notes, and highlights from a KOReader device (bidirectional — the response also returns the server's current state for the book so the device can reconcile).
@@ -52,7 +60,7 @@ KOReader paints highlights from a fixed palette of color names; the web reader u
 
 ### Example Request
 
-```json
+```json example-request
 {
   "book_sha256": "64-hex-char-sha256",
   "bookmarks": [
@@ -83,7 +91,7 @@ KOReader paints highlights from a fixed palette of color names; the web reader u
 
 ## Response (200 OK)
 
-```json
+```json example-response
 {
   "sync_status": "ok",
   "bookmarks_synced": 1,