chore: update .gitignore to include .codex and frontend/.env.local

feat: implement client-side catalog and keys management with loading states and error handling

chore(backend): add .env.example and create_admin seed script

feat(frontend): add all UI components and pages (Iteration 10)

test(frontend): add React Testing Library tests — 57 tests with MSW v2 (Iteration 10)

feat(backend): add metrics dashboard — aggregation queries and admin view (Iteration 9)

test(backend): add metrics TDD tests — service and router (27 tests)

chore(backend): fix lint issues in alembic migrations (Iteration 8 cleanup)

feat(backend): add logs domain — MongoDB observability with masking (Iteration 8)

test(backend): add logs TDD tests — service and router (27 tests)

chore(backend): add Alembic migration — rate_limit column on api_keys

feat(backend): implement rate limiting — sliding window Redis (Iteration 7)

test(backend): add rate limit TDD tests — sliding window Redis (15 tests)

chore(backend): add Alembic migration for request_metrics table

feat(backend): add proxy and metrics domains — Iteration 6 core