Three related issues caused by in-memory agent registry being empty after server restart: 1. JwtAuthenticationFilter rejected valid agent JWTs if agent wasn't in registry — now authenticates any valid JWT regardless 2. Heartbeat returned 404 for unknown agents — now auto-registers the agent from JWT claims (subject, application) 3. SSE endpoint returned 404 — same auto-registration fix JWT validation result is stored as a request attribute so downstream controllers can extract the application claim for auto-registration. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>