Add governed bathymetry profile workflow

docs/API_CONTRACTS.md

@@ -2055,3 +2055,37 @@ specifically, no water volume is inferred from 2D water geometry. The backend
 sets an explicit Ollama context window and returns
 `OLLAMA_RESPONSE_TRUNCATED` instead of accepting a response with
 `done_reason=length` as a complete answer.
+
+## Bathymetry and VHA profile acquisition
+
+### GET `/api/v1/projects/{project_id}/datasets/bathymetry/sources`
+
+Returns the governed bathymetry source registry in the canonical envelope.
+VHA inland profiles are `operational`. MDK Belgian Continental Shelf and SPW
+Walloon bathymetry remain `available_not_integrated`; they cannot be acquired
+through this contract until their raster/download and vertical-datum flows
+pass live validation.
+
+### POST `/api/v1/projects/{project_id}/datasets/bathymetry/profiles/acquire`
+
+```json
+{
+  "bbox": {"min_x": 5.0, "min_y": 51.0, "max_x": 5.3, "max_y": 51.3, "crs": "EPSG:4326"},
+  "area_id": "optional persisted Area uuid",
+  "force_refresh": false
+}
+```
+
+The endpoint creates a synchronous `vector.bathymetry_profiles.acquire` Job.
+It queries the official VHA Digital Atlas in bounded pages, intersects every
+point with the persisted Area when supplied and persists one ordinary
+reference Dataset plus VectorFeature rows. The result reports exact profile,
+document, structured-depth/width and watercourse counts and the source
+measurement-date range.
+
+The acquired Dataset uses
+`source_name=vmm_vha_bathymetry_profiles`,
+`dataset_role=reference` and
+`reference_layer_name=bathymetry_profiles`. Existing vector content and
+selection endpoints provide GeoJSON and metrics. The contract does not expose
+a continuous bathymetric surface, current water depth or water volume.