Merge branch 'worktree-supervisor-flags'

Python supervisor + DB-backed feature flags

- supervisor.py replaces supervisor.sh (topological wave scheduling, croniter)
- workflows.toml workflow registry (5 extractors, cron presets, depends_on)
- proxy.py round-robin + sticky proxy rotation via PROXY_URLS
- Feature flags: migration 0019, is_flag_enabled(), feature_gate() decorator
- Admin /admin/flags UI with toggle (admin-only)
- lead_unlock gate on unlock_lead route
- 59 new tests (test_supervisor.py + test_feature_flags.py)
- Fix is_flag_enabled bug (fetch_one instead of execute_fetchone)

# Conflicts:
#	CHANGELOG.md
#	web/pyproject.toml

web/pyproject.toml

@@ -18,6 +18,7 @@ dependencies = [
     "duckdb>=1.0.0",
     "pyarrow>=23.0.1",
     "pyyaml>=6.0",
+    "croniter>=6.0.0",
     "httpx>=0.27.0",
     "google-api-python-client>=2.100.0",
     "google-auth>=2.23.0",