Extract workbench bootstrap hook

docs/CODEX_EXECUTION_LOG.md

@@ -1,3 +1,33 @@
+## Sprint 43 Workbench bootstrap hook decomposition (2026-06-17)
+
+Changed:
+- Moved frontend bootstrap, project-change reload/reset and detection/segmentation result reload effects from `frontend/src/App.tsx` into `frontend/src/hooks/useWorkbenchBootstrap.ts`.
+- Kept `App.tsx` as a composition root that wires hook outputs into panels; it no longer imports `useEffect`.
+- Extended orchestration tests so lifecycle side effects stay in the bootstrap hook.
+- Updated frontend README, changelog and TODO status.
+
+Validation:
+- `cd backend && python -m pytest tests/test_sprint39_frontend_orchestration_hooks.py -q` passed: 9 tests.
+- `python -m compileall backend/app` passed.
+- `cd backend && python -m pytest -W error::DeprecationWarning` passed: 193 tests.
+- `bash scripts/run_readiness_check.sh` passed.
+- `cd frontend && npm run typecheck` passed.
+- `cd frontend && npm run build` passed.
+- `cd backend && python -m alembic heads` passed: `202606120900 (head)`.
+- `cd backend && python -m alembic upgrade head --sql` passed.
+- `bash -n scripts/live_migration_smoke.sh` passed.
+- `App.tsx` size audit after extraction: 621 lines; `useWorkbenchBootstrap.ts`: 81 lines.
+
+Open:
+- Tower deployment and runtime smoke should run before considering this pass deployed.
+
+Limitations:
+- No UX behavior, API contracts, migrations, provider fetching or AI behavior changed.
+- `App.tsx` line count remains high because it explicitly wires many panel props; the remaining size is primarily composition.
+
+Next recommended pass:
+- Pick the next V1 stabilization focus: UI browser regression coverage, backend service contract audit, or golden dataset expansion.
+
 ## Sprint 42 App entrypoint cleanup (2026-06-17)
 
 Changed: