Remove Buildarch from ldflags, use runtime.GOARCH instead

The architecture is available at runtime via stdlib, no need to bake
it in at build time.

internal/globals/globals.go

@@ -7,25 +7,20 @@ import (
 
 // Build-time variables populated from main() via ldflags.
 var (
-	Appname   string //nolint:gochecknoglobals // set from main
-	Version   string //nolint:gochecknoglobals // set from main
-	Buildarch string //nolint:gochecknoglobals // set from main
+	Appname string //nolint:gochecknoglobals // set from main
+	Version string //nolint:gochecknoglobals // set from main
 )
 
 // Globals holds application-wide constants.
 type Globals struct {
-	Appname   string
-	Version   string
-	Buildarch string
+	Appname string
+	Version string
 }
 
 // New creates a new Globals instance from build-time variables.
 func New(_ fx.Lifecycle) (*Globals, error) {
-	n := &Globals{
-		Appname:   Appname,
-		Buildarch: Buildarch,
-		Version:   Version,
-	}
-
-	return n, nil
+	return &Globals{
+		Appname: Appname,
+		Version: Version,
+	}, nil
 }