feat(api): add request id middleware with client header validation and tracing (#686)

[ravendevhub]

Summary

Resolves #686 by introducing Request ID and Correlation ID tracing middleware for the NotifyChain API, validating client-supplied headers, attaching tracing identifiers to logs, and exposing X-Request-ID in HTTP response headers.

Changes

1. Header Validation (listener/src/middleware/request-id.ts, listener/src/utils/request-id.ts):
   • Validates client-supplied X-Request-ID and X-Correlation-ID headers against safe alphanumeric/hyphen patterns (^[a-zA-Z0-9_-]{1,64}$).
   • Mints secure random UUIDv4 identifiers when client headers are missing or invalid.
2. Response Header Exposure & Logging:
   • Automatically sets X-Request-ID and X-Correlation-ID response headers before flushing.
   • Binds resolved IDs to req.headers for downstream structured log context.
3. Tests & Documentation:
   • Added comprehensive unit tests in request-id.test.ts verifying validation, sanitization, and response binding.
   • Documented contract and integration in docs/REQUEST_ID_MIDDLEWARE.md.

Acceptance Criteria

• Each incoming request receives an identifier.
• The identifier is included in relevant logs.
• Responses expose the identifier where appropriate.
• Client-supplied IDs are validated before reuse.