- Create tRPC router with checkNumber, classifySMS, classifyCall endpoints
- Add protected procedures for rule CRUD, feedback submission, and stats
- Implement service layer with phone number normalization and audit logging
- Add ML engine with BERT stub, feature extraction, and rule engine
- Implement reputation API module with circuit breaker and caching
- Write comprehensive tests (34 tests) for all layers
- Wire spamshield router into app root router
