VSN-2100/ feat(passenger trip tracking): Add GET endpoint for polling latest driver position
This MR adds GET /api/location/driver/latest?driverUuid={uuid} endpoint to enable HTTP polling as an alternative to SSE streaming for user mobile app.
Following tech lead review, the following improvements were added across the service:
- Validation : UUID format validation
- Performance : in-memory position cache, singleflight request coalescing, gzip compression
- Résilience : rate limiting (200 req/min per IP), concurrency semaphore (max 100), MongoDB query timeout (5s)
- HTTP caching : Cache-Control headers, ETag generation with If-None-Match → 304 Not Modified
- Data quality : position freshness check (max 5 min age), invalid coordinates filtered out
- Observabilité : structured zerolog metrics (duration_ms, method, coordinates), OpenAPI annotations