feat: add request logging middleware for backend endpoints

[algojogacor]

Summary

Adds a lightweight onRequest hook to the Fastify backend that logs every incoming request's HTTP method and URL via the existing pino logger infrastructure.

Solution

Added app.addHook('onRequest', ...) in buildApp() that logs { method, url } fields using request.log.info(). This integrates with the existing pino logger configuration and outputs structured log entries for each request.

Changes

• apps/backend/src/app.ts: Added onRequest hook after database/cache plugin registration and before auth decorator. Logs request.method and request.url.
• apps/backend/src/__tests__/app.test.ts (new): Tests that the hook fires on GET and POST requests by spying on app.log.info and verifying the logged fields.

Testing

• Test file created with two test cases:
  • Verifies GET /health produces log entry with { method: 'GET', url: '/health' }
  • Verifies POST /api/u/testuser produces log entry with { method: 'POST', url: '/api/u/testuser' }
• Tests use Fastify's inject() method for lightweight HTTP testing
• Tests pass when run with a configured database (Prisma requires database connection)

[ShantKhatri]

@algojogacor Thanks for the PR. This is not yet discussed, and I'm not to understand the change here. could you please add detailed explaination here, happy to look into this.