Seed system reference values, readiness required-field rules, and overdue milestone escalation defaults during application startup.

Add idempotent seed-key storage with source metadata so reruns avoid duplicates and preserve admin-managed values. Replace the corrupted seed test file with coverage for first seed, persistence, idempotency, FR29 readiness scope, FR30 escalation defaults, and admin override preservation.

- Add JWT bearer auth, session endpoint, and auth audit capture
- Add server-side Keycloak token exchange and refresh endpoints
- Load Keycloak client secret from ignored .env file
- Configure Canopy Keycloak realm, CORS, and Vite API proxy
- Add frontend protected auth callback, token storage, and refresh handling
- Cover backend and frontend auth behavior with tests