feat: anonymous usage telemetry via oss-telemetry

Send a single fire-and-forget ping at startup to help track adoption
and version spread. No persistent identifiers are collected.

Adds main.appVersion var (defaulting to "dev"); wire ldflags
(-X main.appVersion=$VERSION) to populate it at release time.

Opt out via any of:
  DO_NOT_TRACK=1
  OSS_TELEMETRY_DISABLED=1
  GRAPHQL_MONITORING_PROXY_DISABLE_TELEMETRY=1

main.go

@@ -28,11 +28,17 @@ import (
 	libpack_logging "github.com/lukaszraczylo/graphql-monitoring-proxy/logging"
 	libpack_monitoring "github.com/lukaszraczylo/graphql-monitoring-proxy/monitoring"
 	libpack_tracing "github.com/lukaszraczylo/graphql-monitoring-proxy/tracing"
+	telemetry "github.com/lukaszraczylo/oss-telemetry"
 
 	// Auto-tune GOMAXPROCS from cgroup CPU quota (containerized workloads).
 	_ "go.uber.org/automaxprocs"
 )
 
+// appVersion is the build version. Set via ldflags during build:
+//
+//	-X main.appVersion=v1.2.3
+var appVersion = "dev"
+
 var (
 	cfg             *config
 	cfgMutex        sync.RWMutex
@@ -512,6 +518,8 @@ func parseConfig() {
 }
 
 func main() {
+	telemetry.Send("graphql-monitoring-proxy", appVersion)
+
 	// Parse configuration
 	parseConfig()