Update documentation and API tests: Bookmann → Bookhoard

Documentation updates:
- All docs/ files: Update project references
- Bruno API collection: Update collection name and tests
- Device setup guides: Update all examples
- Implementation plan: Update database schema examples
- README files: Update project references

Part of project rename to Bookhoard.

docs/API_REFERENCE.md

@@ -657,7 +657,7 @@ Content-Type: application/json
 {
   "device_id": "uuid",
   "registration_id": "registration-uuid",
-  "auth_url": "https://bookmann.com/devices/auth/confirm/abc123",
+  "auth_url": "https://bookhoard.com/devices/auth/confirm/abc123",
   "qr_code": "data:image/png;base64,iVBORw0KG...",
   "expires_in": 300
 }
@@ -681,9 +681,9 @@ Content-Type: application/json
   "auth_token": "device-bearer-token...",
   "device_id": "uuid",
   "sync_endpoints": {
-    "progress": "https://bookmann.com/api/sync/progress",
-    "metadata": "https://bookmann.com/api/sync/metadata",
-    "annotations": "https://bookmann.com/api/sync/annotations"
+    "progress": "https://bookhoard.com/api/sync/progress",
+    "metadata": "https://bookhoard.com/api/sync/metadata",
+    "annotations": "https://bookhoard.com/api/sync/annotations"
   }
 }
 ```