docs(api): add universal progress tracking documentation

- get_universal_progress.md - GET /api/progress/:id
- update_universal_progress.md - POST /api/progress/:id
- get_progress_history.md - GET /api/progress/:id/history

Documents device-agnostic (universal) reading progress tracking
that works across all devices (Kobo, KOReader, etc.)

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

@@ -0,0 +1,54 @@
+# Get Device File Aliases
+
+Get all file aliases for a specific device.
+
+**Endpoint**: `GET /api/devices/:id/file-aliases`
+**Auth**: Required
+
+## Path Parameters
+
+| Parameter | Type | Required | Description |
+|-----------|------|-----------|-------------|
+| id | string (UUID) | Yes | Device UUID |
+
+## Request Headers
+
+| Header | Type | Required | Description |
+|--------|------|-----------|-------------|
+| Authorization | string | Yes | Bearer token |
+
+### Example Request
+
+```http
+GET /api/devices/550e8400-e29b-41d4-a716-446655440000/file-aliases
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+## Response (200 OK)
+
+```json
+{
+  "aliases": [
+    {
+      "id": "uuid",
+      "device_id": "device-uuid",
+      "media_item_id": "book-uuid",
+      "file_name": "book.epub",
+      "file_hash": "sha256hash",
+      "created_at": "2026-02-08T10:00:00Z"
+    }
+  ],
+  "total": 23
+}
+```
+
+## Error Responses
+
+| Code | Description |
+|------|-------------|
+| 401 | Invalid or expired token |
+| 404 | Device not found |
+
+## Try It Out
+
+<!-- API Explorer will be inserted here in Phase 3 -->