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_sprint234_project_lifecycle_cleanup.py

@@ -15,6 +15,7 @@ from app.api.routes import projects as project_routes
 from app.main import app
 from app.schemas.project import ProjectRead, ProjectUpdate
 from app.services.project_service import ProjectService
+from tests.frontend_contract import read_feature
 
 
 ROOT = Path(__file__).resolve().parents[2]
@@ -149,11 +150,11 @@ def test_cleanup_script_can_start_as_a_direct_operator_command() -> None:
 
 
 def test_frontend_lifecycle_and_component_boundaries_are_wired() -> None:
-    app_source = (ROOT / "frontend/src/App.tsx").read_text(encoding="utf-8")
+    app_source = read_feature("shell")
     project_panel = (ROOT / "frontend/src/components/project/ProjectPanel.tsx").read_text(encoding="utf-8")
-    detection_lab = (ROOT / "frontend/src/components/detection/DetectionLab.tsx").read_text(encoding="utf-8")
-    segmentation_lab = (ROOT / "frontend/src/components/segmentation/SegmentationLab.tsx").read_text(encoding="utf-8")
-    map_workspace = (ROOT / "frontend/src/components/map/MapWorkspace.tsx").read_text(encoding="utf-8")
+    detection_lab = read_feature("detection")
+    segmentation_lab = read_feature("segmentation")
+    map_workspace = read_feature("map_workspace")
     premium_css = (ROOT / "frontend/src/styles/premium.css").read_text(encoding="utf-8")
 
     assert "OverviewWorkspace" in app_source