Enhance API and UI for incident management and live updates

- Added a new endpoint `/api/agg/incidents` to provide a normalized snapshot of incidents for fleet triage, including severity and recommended actions.
- Implemented live event streaming via `/api/live/events` for real-time updates on fleet status and incidents, enhancing observability.
- Updated the Web UI to include dedicated sections for incidents and live updates, improving user navigation and access to critical information.
- Enhanced API documentation to reflect new endpoints and their functionalities, ensuring clarity for developers and users.

internal/server/metrics.go

@@ -15,17 +15,17 @@ var (
 	})
 	httpRequests = promauto.NewCounterVec(prometheus.CounterOpts{
 		Name: "telemt_gateway_http_requests_total",
-		Help: "HTTP requests by status, method, alias.",
-	}, []string{"code", "method", "alias"})
+		Help: "HTTP requests by status, method, alias, endpoint.",
+	}, []string{"code", "method", "alias", "endpoint"})
 	httpDuration = promauto.NewHistogramVec(prometheus.HistogramOpts{
 		Name:    "telemt_gateway_http_request_duration_seconds",
 		Help:    "Request duration in seconds.",
 		Buckets: prometheus.DefBuckets,
-	}, []string{"method", "alias"})
+	}, []string{"method", "alias", "endpoint"})
 )
 
-func observeRequest(method, alias string, status int, started time.Time) {
+func observeRequest(method, alias, endpoint string, status int, started time.Time) {
 	httpInFlight.Dec()
-	httpRequests.WithLabelValues(strconv.Itoa(status), method, alias).Inc()
-	httpDuration.WithLabelValues(method, alias).Observe(time.Since(started).Seconds())
+	httpRequests.WithLabelValues(strconv.Itoa(status), method, alias, endpoint).Inc()
+	httpDuration.WithLabelValues(method, alias, endpoint).Observe(time.Since(started).Seconds())
 }