docs(api): add KOReader sync protocol documentation

- sync_progress.md - POST /api/sync/koreader/progress
- get_metadata.md - GET /api/sync/koreader/metadata/:uuid
- get_library.md - GET /api/sync/koreader/library
- sync_bookmarks.md - POST /api/sync/koreader/bookmarks

KOReader device sync endpoints with device authentication
for progress, metadata, library, and bookmarks

docs/developer/api/conflicts/get_conflict.md

@@ -0,0 +1,79 @@
+# Get Conflict Details
+
+Get detailed information about a specific conflict.
+
+**Endpoint**: `GET /api/conflicts/:id`
+**Auth**: Required
+
+## Path Parameters
+
+| Parameter | Type | Required | Description |
+|-----------|------|-----------|-------------|
+| id | string (UUID) | Yes | Conflict UUID |
+
+## Request Headers
+
+| Header | Type | Required | Description |
+|--------|------|-----------|-------------|
+| Authorization | string | Yes | Bearer token |
+
+### Example Request
+
+```http
+GET /api/conflicts/550e8400-e29b-41d4-a716-446655440000
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+## Response (200 OK)
+
+```json
+{
+  "id": "uuid",
+  "media_item": {
+    "id": "book-uuid",
+    "title": "Sample Book",
+    "authors": ["Author Name"]
+  },
+  "device_progress": {
+    "device_id": "device-uuid",
+    "device_name": "My Kobo",
+    "percentage": 75,
+    "position": 1234,
+    "page": 150,
+    "updated_at": "2026-02-08T10:00:00Z"
+  },
+  "server_progress": {
+    "percentage": 50,
+    "position": 800,
+    "page": 100,
+    "updated_at": "2026-02-08T09:00:00Z"
+  },
+  "device_bookmarks": [
+    {
+      "position": 1234,
+      "text": "Interesting passage",
+      "created_at": "2026-02-08T10:00:00Z"
+    }
+  ],
+  "server_bookmarks": [
+    {
+      "position": 800,
+      "text": "Another passage",
+      "created_at": "2026-02-07T15:00:00Z"
+    }
+  ],
+  "status": "active",
+  "created_at": "2026-02-08T10:00:00Z"
+}
+```
+
+## Error Responses
+
+| Code | Description |
+|------|-------------|
+| 401 | Invalid or expired token |
+| 404 | Conflict not found |
+
+## Try It Out
+
+<!-- API Explorer will be inserted here in Phase 3 -->