Add local model asset catalog

docs/AI_PIPELINES.md

@@ -100,6 +100,7 @@ Environment variables:
 
 - `GEOINTEL_INSTALL_AI`
 - `YOLO_ENABLED`
+- `YOLO_MODELS_DIR`
 - `YOLO_MODEL_PATH`
 - `YOLO_MODEL_ID`
 - `YOLO_MODEL_DISPLAY_NAME`
@@ -109,6 +110,19 @@ Environment variables:
 - `YOLO_MAX_TILES`
 - `YOLO_BATCH_SIZE`
 
+### Local model asset catalog
+
+GeoIntel can list local runtime model files mounted into the backend model
+directory through `GET /api/v1/detection/model-assets`. The catalog is
+filesystem-backed and read-only: it reports existing `.pt`, `.onnx` and
+`.engine` files, size, checksum and whether the file matches `YOLO_MODEL_PATH`.
+
+Detection runs still use `model_id="yolo-configured"` for the configured YOLO
+execution path. A selected `model_asset_id` can be supplied to use one specific
+cataloged file for that run. The backend resolves the ID to a local path and
+persists the selected asset metadata in Job/AnalysisRun parameters. GeoIntel
+does not download weights or accept arbitrary model paths from the browser.
+
 ### Sprint 8C detection visualization and QA status
 
 Sprint 8C makes persisted detections reviewable: