feat(core): harden GuildPass Core V2 for production readiness (#422)

[rupesh-kumar-sah]

Summary

Closes #422

Hardens GuildPass Core V2 for production readiness with end-to-end authorization boundaries, idempotency, structured redacted logging, typed error handling, sliding-window rate limiting, predictable Stellar transaction failure handling with circuit breakers, and observability probes.

Implemented Architecture & Controls

1. Mutation Authorization Boundary (src/security/auth.ts):

   • Integrated @guildpass/capability-token to verify incoming Bearer capability tokens.
   • Enforced route guards (requireAuth, requireScopes, requireAnyScope) requiring explicit scopes (e.g., pass:issue, pass:revoke, stellar:submit) before any state mutation can proceed.
   • Unauthorized or unauthenticated mutations return controlled 401 AUTH_UNAUTHORIZED or 403 AUTH_FORBIDDEN errors.

2. Idempotency Protection (src/plugins/idempotency.ts):

   • Integrated @guildpass/idempotency and @guildpass/canonical-json into a Fastify plugin.
   • Computes deterministic SHA-256 fingerprints across HTTP method, endpoint URL, and canonical JSON body.
   • Accurately identifies cached replays, returning cached responses with header Idempotent-Replay: true.
   • Protects against in-flight race conditions and payload mismatches by returning 409 IDEMPOTENCY_CONFLICT.

3. Sensitive Value Redaction & Structured Logging (src/observability/logging.ts):

   • Integrated @guildpass/log-redaction across Fastify request and response hooks.
   • Automatically redacts authorization headers, cookies, API keys, private keys, seed phrases, and passwords recursively before writing to structured logs.
   • Propagates distributed x-correlation-id across all log entries and client responses.

4. Sanitized Typed Error Hierarchy (src/errors/index.ts):

   • Implemented GuildPassError hierarchy (AuthenticationError, AuthorizationError, ValidationError, NotFoundError, ConflictError, RateLimitExceededError, IdempotencyConflictError, StellarTransactionError, InternalServerError).
   • Centralized errorHandlerPlugin sanitizes all public error payloads, masking stack traces, internal connection strings, and sensitive credentials while attaching correlation IDs.

5. Sliding-Window Rate Limiting (src/plugins/rate-limit.ts):

   • Integrated @guildpass/rate-limit with sliding window counters.
   • Emits standard X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, and Retry-After headers.
   • Returns typed 429 RATE_LIMIT_EXCEEDED errors when limits are exceeded.

6. Predictable Stellar Transaction Resilience (src/stellar/transaction-handler.ts):

   • Implemented classifyStellarError categorizing errors into permanent (e.g., tx_bad_auth, op_underfunded, tx_insufficient_fee) vs transient (e.g., tx_bad_seq, HTTP 503, connection timeouts).
   • Integrated @guildpass/retry-policy with exponential backoff and jitter to automatically retry transient errors while immediately fast-failing non-retryable errors.
   • Integrated @guildpass/circuit-breaker to trip to OPEN state after consecutive downstream RPC failures, protecting the service from connection pool exhaustion.

7. Observability: Liveness & Readiness Probes (src/observability/health.ts):

   • /health: Fast liveness check returning { status: "ok", service: "guildpass-core-api" }.
   • /ready: Detailed readiness check evaluating memory consumption, system health, and external dependencies.

8. Comprehensive Automated Test Suite (src/test/hardening.test.ts):

   • 22/22 unit and integration tests verifying all 8 production readiness acceptance criteria.

Acceptance Criteria Verification

• Mutation authorization is explicitly enforced or delegated through a documented boundary.
• Appropriate operations support idempotency.
• Sensitive values are not exposed through logs or public errors.
• Structured logging is available for important Core operations.
• Infrastructure failures produce controlled typed errors.
• Stellar transaction failure states are handled predictably.
• Security-focused tests cover critical access and mutation paths.
• CI passes all typecheck, test, build, and security-related checks required by the repository.

[Lakes41]

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