docs(highlights,notes,opds,progress,analytics): Beam batch 9 — 13 endpoints

Highlights + notes CRUD (media-item scoped, jwt), progress delete,
reading-stats analytics, and the OPDS trio frontmatter'd. OPDS docs are
the first XML entries: example-response intentionally omitted (Atom
responses), gate contract honored via nil-Response registry pins.

Gate fix: group .Use() middleware now parsed (opds.Use(DeviceAuth...
Authenticate) previously resolved to auth 'none'). Registry: 13 entries.
Drift fixed by gate: reading-stats key names (total_reading_time_minutes,
most_active_day_of_week, daily_reading_minutes — draft invented
reading_time_hours/books_completed); notes/highlights list endpoints
return BARE arrays (no {notes:[]}/{highlights:[]} wrapper); create-note
request has no percentage_location/epubcfi_location. New
/tmp/merge_arrays.py handles array-example merges.

make test 9/9.

docs/developer/api/notes/get_notes.md

@@ -1,3 +1,11 @@
+---
+method: GET
+path: /api/media-items/:id/notes
+auth: jwt
+area: media-items
+---
+<!-- source: internal/handlers/media.go:1851 MediaHandler.GetMediaNotes -->
+
 # Get Notes
 
 Retrieve all notes for a specific media item.
@@ -26,26 +34,34 @@ Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
 
 ## Response (200 OK)
 
-```json
-{
-  "notes": [
-    {
-      "id": "uuid",
-      "media_item_id": "uuid",
-      "user_id": "uuid",
-      "content": "This is an interesting passage...",
-      "position": "epubcfi(/6/4/2:15)",
-      "percentage_location": 0.45,
-      "character_start": 15432,
-      "character_end": 15480,
-      "epubcfi_location": "epubcfi(/6/4/2:15)",
-      "created_at": "2026-01-31T10:00:00Z",
-      "updated_at": "2026-01-31T10:00:00Z"
-    }
-  ]
-}
+```json example-response
+[
+  {
+    "id": "uuid",
+    "media_item_id": "uuid",
+    "user_id": "uuid",
+    "content": "This is an interesting passage...",
+    "position": "epubcfi(/6/4/2:15)",
+    "percentage_location": 0.45,
+    "character_start": 15432,
+    "character_end": 15480,
+    "epubcfi_location": "epubcfi(/6/4/2:15)",
+    "created_at": "2026-01-31T10:00:00Z",
+    "updated_at": "2026-01-31T10:00:00Z",
+    "chapter_reference": null,
+    "dedup_key": "",
+    "deleted": false,
+    "deleted_at": null,
+    "device_sync_data": "",
+    "last_modified_at": null,
+    "last_modified_source": "",
+    "paragraph_reference": null
+  }
+]
 ```
 
+Response is a bare JSON array of MediaNotes rows — no wrapper object.
+
 ## Error Responses
 
 | Code | Description              |