Feature Flags API
- Added six live routes under
/api/v1/flagsfor definitions, deterministic user assignments, exposure tracking, listing, and cleanup. - Added Lua and JavaScript SDK helpers plus a self-test that writes a flag, assigns a variant, records exposure, lists, reads, and deletes it.
- Added API workbench, Studio tester, key product, docs, status, and public route count coverage for the new module.