Add local model asset catalog

backend/README.md

@@ -125,6 +125,7 @@ bash scripts/live_migration_smoke.sh
   - detection service boundary for creating jobs, analysis runs and dependency-aware unavailable responses.
 - Added detection endpoints:
   - `GET /api/v1/detection/models`
+  - `GET /api/v1/detection/model-assets`
   - `POST /api/v1/detection/run`
   - `GET /api/v1/detection/runs/{analysis_run_id}`
   - `GET /api/v1/detection/runs/{analysis_run_id}/detections`
@@ -239,6 +240,7 @@ Configured YOLO requires:
 
 ```bash
 YOLO_ENABLED=true
+YOLO_MODELS_DIR=/absolute/path/to/models
 YOLO_MODEL_PATH=/absolute/path/to/local-model.pt
 ```
 
@@ -260,6 +262,7 @@ directory, mounted as `/app/models` by default:
 ```bash
 GEOINTEL_MODELS_PATH=/mnt/user/appdata/geointel/models
 YOLO_ENABLED=true
+YOLO_MODELS_DIR=/app/models
 YOLO_MODEL_PATH=/app/models/local-model.pt
 ```
 
@@ -275,6 +278,19 @@ python scripts/configure_yolo_model.py \
 The smoke loads only the supplied local model file, does not run inference and
 does not download weights.
 
+The backend also exposes a read-only model asset catalog for the mounted model
+directory:
+
+```bash
+curl http://localhost:1202/api/v1/detection/model-assets
+```
+
+The catalog lists local `.pt`, `.onnx` and `.engine` files with size, SHA-256
+and active-model status. Detection runs may submit `model_asset_id` with
+`model_id="yolo-configured"` to use a cataloged local model for that run. The
+backend resolves the ID to a file inside `YOLO_MODELS_DIR`; browser clients do
+not send arbitrary model paths.
+
 Configured YOLO inference uses raster tile artifacts from the existing tile
 manifest flow. Single-band or otherwise non-RGB tile images are converted to a
 temporary RGB prediction image before inference; georeferencing still comes
@@ -286,6 +302,7 @@ Optional tuning:
 YOLO_MODEL_ID=yolo-configured
 YOLO_MODEL_DISPLAY_NAME="Configured YOLO detector"
 YOLO_MODEL_VERSION=local-v1
+YOLO_MODELS_DIR=/app/models
 YOLO_CONFIG_DIR=/app/storage/ultralytics
 YOLO_DEVICE=cpu
 YOLO_IMAGE_SIZE=640