feat: move module path to git.unbound.se

The module is now git.unbound.se/shiny/otelsetup. The API is unchanged. Tags up to v0.7.0 declare gitea.unbound.se/shiny/otelsetup and stay resolvable through that alias. The eventsourced and subscription meter names keep the old path on purpose: they are OTel scope names, not import paths.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Kko4x3MYEcWMMdkx12WpBa

subscription_metrics.go

@@ -10,6 +10,7 @@ import (
 
 // subscriptionMeterName is the instrumentation scope for the cross-service
 // subscription push metrics emitted by SubscriptionMetrics.
+// It keeps the old module path on purpose: renaming it breaks queries on otel_scope_name.
 const subscriptionMeterName = "gitea.unbound.se/shiny/otelsetup/subscriptions"
 
 // SubscriptionMetrics records cross-service subscription push outcomes (the
@@ -17,7 +18,7 @@ const subscriptionMeterName = "gitea.unbound.se/shiny/otelsetup/subscriptions"
 // counters.
 //
 // Its method set (Pushed/PushSkipped/Dropped/ChannelFull) satisfies the
-// Observer interface of gitea.unbound.se/shiny/subscriptions *structurally* —
+// Observer interface of git.unbound.se/shiny/subscriptions *structurally* —
 // otelsetup does not import that library. A service constructs it and passes it
 // to the registry:
 //