Security fixes based on adversarial audit: 1. CSRF Protection (CRITICAL) - Added CSRF middleware with double-submit cookie pattern - All POST forms now include hidden _csrf field - Tokens validated on all state-changing requests 2. Private Key Permissions (HIGH) - Private key now written with mode 0600 (owner read/write only) - Prevents other system users from reading the key 3. Input Validation (MEDIUM) - Added TID format validation for rkey parameters - Prevents potential path traversal or injection via malformed IDs 4. Added validation library for future use - TID validation - HTTPS URL validation - String sanitization helper Co-authored-by: Shelley <shelley@exe.dev>