- Fix HTML injection vulnerability with proper entity encoding
- Fix rate limit cleanup bug (count vs timestamp confusion)
- Add URL validation to prevent open redirect attacks
- Add expiration to in-memory deduplication entries
- Use Zod schema for config validation
- Add email format validation
All 29 tests passing. Ready for Code Reviewer final review.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
- Add ioredis dependency for Redis connection pooling
- Create RedisService singleton with connection management
- Add Redis config (url, dedupWindowSeconds) to notification.config.ts
- Implement NotificationService.checkRateLimit using Redis INCR+EXPIRE
- Implement NotificationService.deduplicateNotification using Redis SET/NX
- Add configurable rate limit windows and thresholds via env vars
- Add 29 unit tests covering Redis operations, rate limiting, and dedup
- All tests pass, TypeScript compiles cleanly for new files
