add prometheus instrumentation

server/handler/metrics.go

@@ -0,0 +1,17 @@
+package handler
+
+import (
+	"net/http"
+	"vctp/internal/metrics"
+)
+
+// Metrics exposes Prometheus metrics.
+// @Summary Prometheus metrics
+// @Description Exposes Prometheus metrics for vctp.
+// @Tags metrics
+// @Produce plain
+// @Success 200 "Prometheus metrics"
+// @Router /metrics [get]
+func (h *Handler) Metrics(w http.ResponseWriter, r *http.Request) {
+	metrics.Handler().ServeHTTP(w, r)
+}