docs(api): add sync queue management documentation

- get_device_queue_stats.md - Get queue statistics for device
- list_device_queue_items.md - List queue items with filtering
- retry_queue_item.md - Retry failed queue items
- delete_queue_item.md - Delete queue items
- clear_device_queue.md - Clear entire device queue
- list_all_queue_items.md - List all queue items (admin)

Documents sync queue management for handling failed/queued operations
between devices and server

docs/developer/api/devices/update_device.md

@@ -0,0 +1,56 @@
+# Update Device
+
+Update a device's information.
+
+**Endpoint**: `PUT /api/devices/:id`
+**Auth**: Required
+**Content-Type**: `application/json`
+
+## Path Parameters
+
+| Parameter | Type | Required | Description |
+|-----------|------|-----------|-------------|
+| id | string (UUID) | Yes | Device UUID |
+
+## Request Body
+
+| Field | Type | Required | Description |
+|--------|------|-----------|-------------|
+| name | string | No | Device display name |
+| device_type | string | No | Device type (kobo, koreader, etc.) |
+
+### Example Request
+
+```json
+{
+  "name": "My Kobo Clara",
+  "device_type": "kobo"
+}
+```
+
+## Response (200 OK)
+
+```json
+{
+  "id": "uuid",
+  "name": "My Kobo Clara",
+  "device_type": "kobo",
+  "user_id": "user-uuid",
+  "status": "active",
+  "created_at": "2026-02-08T10:00:00Z",
+  "updated_at": "2026-02-08T11:00:00Z"
+}
+```
+
+## Error Responses
+
+| Code | Description |
+|------|-------------|
+| 400 | Invalid request data |
+| 401 | Invalid or expired token |
+| 403 | Device does not belong to user |
+| 404 | Device not found |
+
+## Try It Out
+
+<!-- API Explorer will be inserted here in Phase 3 -->