Add demo export cleanup tooling

docs/CODEX_EXECUTION_LOG.md

@@ -1,3 +1,23 @@
+## Sprint 24 demo/export artifact cleanup tooling (2026-06-17)
+
+Changed:
+- Added `scripts/cleanup_demo_artifacts.py` for dry-run-first cleanup of old offline demo export artifacts.
+- Cleanup is constrained to an exact demo project name by default, keeps the newest exports per project and refuses file deletion outside `STORAGE_ROOT`.
+- Added regression tests for cleanup selection, path safety and readiness gate coverage.
+- Added Python compile validation for the cleanup script to `scripts/run_readiness_check.sh`.
+- Documented cleanup usage in `scripts/README.md`, `docs/STORAGE_ARCHITECTURE.md`, `backend/README.md`, `docs/TODO.md` and `CHANGELOG.md`.
+
+Validation:
+- `python -m py_compile scripts/cleanup_demo_artifacts.py` passed.
+- `python -m pytest backend/tests/test_sprint24_cleanup_demo_artifacts.py backend/tests/test_readiness_gate.py` passed: 10 tests.
+- `bash scripts/run_readiness_check.sh` passed: 151 backend tests, frontend typecheck/build, Alembic head check and script syntax checks.
+- `python -m compileall backend/app` passed.
+- `cd backend && python -m alembic upgrade head --sql` passed.
+- `bash -n scripts/live_migration_smoke.sh` and `bash -n scripts/verify_demo_export_workflow.sh` passed.
+- Local `docker compose config` could not run because the Windows Docker CLI is not installed in this Codex environment.
+
+Notes:
+- No API contracts, migrations, product features, provider fetching, AI inference or source dataset cleanup behavior changed.
 ## Sprint 23 V1 report handoff summary (2026-06-17)
 
 Changed:
@@ -385,7 +405,7 @@ Date: 2026-06-11
 
 ### Next recommended pass
 - Run full raster end-to-end tests with real GeoTIFF fixtures and validate output dataset metadata persistence.
-## Pass 16 — Sprint 4 raster operations foundation hardening
+## Pass 16 � Sprint 4 raster operations foundation hardening
 Date: 2026-06-11
 
 ### Completed