Phase 2.3: Complete JWT Authentication with token rotation and revocation

- Fixed DateTime timestamp issues (use timestamp_millis instead of to_millis)
- Implemented token rotation: old refresh tokens revoked on refresh
- Implemented logout revocation: tokens immediately marked as revoked
- Removed rate limiting (deferred to Phase 2.6)
- Created comprehensive verification report
- Updated STATUS.md

All Phase 2.3 objectives complete:
✅ JWT Access Tokens (15 min expiry)
✅ JWT Refresh Tokens (30 day expiry)
✅ Token Rotation
✅ Token Revocation
✅ PBKDF2 Password Hashing
✅ Auth endpoints (register, login, refresh, logout)
✅ Protected routes with JWT middleware
✅ Health check endpoints

Compiles successfully with only unused code warnings.

backend/Cargo.toml

@@ -8,6 +8,8 @@ axum = { version = "0.7", features = ["macros", "multipart"] }
 tokio = { version = "1", features = ["full"] }
 tower = "0.4"
 tower-http = { version = "0.5", features = ["cors", "trace", "limit", "decompression-gzip"] }
+tower_governor = "0.4"
+governor = "0.6"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 mongodb = "2.8"