Security fixes:
- Register route validates company exists before creating user
- Rate limiting on auth routes (10 per 15min per IP)
- Dev auth plugin guards against production use
- Main.ts throws if JWT_SECRET missing in production
Added Phase 2 audit doc (22) covering:
- Built vs planning doc comparison
- Security review with fixes applied
- Duplicate code patterns identified
- Standard POS feature gap analysis
- Music-specific feature gaps
33 tests passing.