scope frontend contracts to the feature, not to one file

93 test files read a single frontend source and asserted identifiers in it. The
MapWorkspace split showed what that costs: 24 tests went red for a move that
changed no behaviour at all. A contract belongs to the feature — a container,
its hooks, its domain layer — not to whichever file currently holds it.

232 read sites now resolve through read_feature(). The distinction that makes
this safe is direction: a *positive* contract ("this is wired") may widen,
because the identifier must still exist somewhere in the feature; a *negative*
one ("this component performs no transport") is a statement about one file, and
widening it would quietly weaken the check. The 73 single-file reads that
remain are exactly those, and a guard now enforces the rule for new tests.

Verified rather than assumed: of the 732 migrated positive assertions, 644 still
match exactly one module — as specific as before — and the other 86 already
spanned a container and its hook by nature. Two apparent misses are an artefact
of the checking regex reading an escaped newline literally.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/tests/test_sprint205_dhmv_terrain.py

@@ -21,7 +21,7 @@ from app.models import Area, Dataset, DatasetVersion, Job, Project, SourceRegist
 from app.schemas.dhmv import DhmvAcquireRequest, TerrainPartitionSelectionRequest, TerrainSelectionRequest
 from app.services.dhmv_acquisition_service import DhmvAcquisitionService
 from app.services.terrain_analysis_service import TerrainAnalysisService
-from tests.frontend_contract import read_map_workspace
+from tests.frontend_contract import read_map_workspace, read_feature
 
 
 ROOT = Path(__file__).resolve().parents[2]
@@ -618,8 +618,8 @@ def test_frontend_and_runtime_expose_dhmv_workflow() -> None:
         ROOT / "frontend" / "src" / "lib" / "datasetCapabilities.ts"
     ).read_text(encoding="utf-8")
     map_source = read_map_workspace()
-    hook_source = (ROOT / "frontend" / "src" / "hooks" / "useMapSelectionExtract.ts").read_text(encoding="utf-8")
-    service_source = (ROOT / "frontend" / "src" / "services" / "api" / "datasets.ts").read_text(encoding="utf-8")
+    hook_source = read_feature("map_workspace")
+    service_source = read_feature("datasets")
 
     assert "digitaal_vlaanderen_dhmv" in capabilities_source
     assert "isMapRasterDataset" in capabilities_source