docs: update CHANGELOG and PROJECT.md for supervisor + feature flags

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,26 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 ## [Unreleased]
 
 ### Added
+- **Python supervisor** (`src/padelnomics/supervisor.py`) — replaces `supervisor.sh`;
+  reads `infra/supervisor/workflows.toml` (module, schedule, entry, depends_on,
+  proxy_mode); runs due workflows in topological waves (parallel within each wave);
+  croniter-based `is_due()` check; systemd service updated to use `uv run python`
+- **`workflows.toml` workflow registry** — 5 extractors registered: overpass,
+  eurostat, playtomic_tenants, playtomic_availability, playtomic_prices; cron
+  presets: hourly/daily/weekly/monthly; `playtomic_availability` depends on
+  `playtomic_tenants`
+- **`proxy.py` proxy rotation** (`extract/padelnomics_extract/proxy.py`) — reads
+  `PROXY_URLS` env var; `make_round_robin_cycler()` for thread-safe round-robin;
+  `make_sticky_selector()` for consistent per-tenant proxy assignment (hash-based)
+- **DB-backed feature flags** — `feature_flags` table (migration 0019);
+  `is_flag_enabled(name, default)` helper; `feature_gate(flag, template)` decorator
+  replaces `WAITLIST_MODE`/`waitlist_gate`; 5 flags seeded: `markets` (on),
+  `payments`, `planner_export`, `supplier_signup`, `lead_unlock` (all off)
+- **Admin feature flags UI** — `/admin/flags` lists all flags with toggle;
+  `POST /admin/flags/toggle` flips enabled bit; requires admin role; flash message
+  on unknown flag
+- **`lead_unlock` gate** — `unlock_lead` route returns HTTP 403 when `lead_unlock`
+  flag is disabled
 - **Playtomic full data extraction** — expanded venue bounding boxes from 4 regions
   (ES, UK, DE, FR) to 23 globally (Italy, Portugal, NL, BE, AT, CH, Nordics, Mexico,
   Argentina, Middle East, USA); PAGE_SIZE increased from 20 to 100; availability