Add Request Logging Middleware

[sorochak]

Introduce a FastAPI middleware that logs request metadata and performance metrics for all API routes.

Tasks

• Implement @app.middleware("http") in main.py
• Log the following per request:
  • Client IP address
  • HTTP method (GET, POST, etc.)
  • Request path
  • Response status code
  • Request duration (in seconds)
  • User-Agent header
• Format logs for readability (or optionally as structured JSON)
• Use uvicorn.access or __name__ logger depending on log pipeline
• Ensure no sensitive data (e.g. file contents or auth tokens) are logged