feat: setup structured logging infrastructure

[kike-alt]

Summary

Implements structured logging infrastructure using Pino as required by issue #310.

Implementation Details

New Files

• src/common/middleware/logging.middleware.ts — Request/response logging middleware that attaches a x-correlation-id header to every request (reuses existing header if provided), logs incoming requests and response completions with method, URL, status code, duration, and IP.
• src/common/middleware/logging.middleware.spec.ts — Unit tests for both the logger config and LoggingMiddleware (8 tests, all passing).

Modified Files

• src/app.module.ts — Registered LoggingMiddleware globally via NestModule.configure() for all routes.
• src/config/logger.ts — Fixed circular dependency with tracing.ts by replacing the top-level import { getCurrentTraceId } with a lazy require() call inside the mixin function.
• src/config/tracing.ts — Replaced all console.log/console.error calls with structured pino logger calls. Used lazy require('./logger') to avoid circular dependency.
• src/common/database/database-index.service.ts — Replaced console.log/console.warn/console.error with structured logger calls.
• src/oracle/submission-verifier.service.ts — Replaced console.warn with structured logger.warn call.

Validation Results

• ✅ Build: webpack compiled successfully
• ✅ New tests: 8/8 pass (logging.middleware.spec.ts)
• ✅ No console.log/warn/error remaining in source code (excluding JSDoc comments)
• ℹ️ Pre-existing test failures: 10 suites fail due to unrelated module resolution issues (Cannot find module 'src/...') — confirmed pre-existing on main before this PR

Closes

Closes #310