ff59d9f799
- Remove CORS origin reflection (SEC-C1 CRITICAL) - Add Content-Security-Policy header (SEC-H2) - Fix rate limiter memory leak with periodic stale IP cleanup (SEC-H5) - Enforce minimum 32-char ENCRYPTION_KEY (SEC-H4) - Validate backup type against allowlist (SEC-M6) - Fix backup download path traversal with path containment check (SEC-C2 CRITICAL)