style(frontend): gofmt the apiserver and xcecli sources

Formatting only (gofmt -w on the 29 non-vendored, non-generated files
gofmt -l reported); swag-generated apiserver/docs/docs.go left as is.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/frontend/apiserver/backend/auth/config_file_test.go

@@ -23,10 +23,10 @@ config_file:
 	}
 
 	tests := []struct {
-		name     string
-		user     string
-		pass     string
-		wantErr  bool
+		name    string
+		user    string
+		pass    string
+		wantErr bool
 	}{
 		{"valid admin", "admin", "secret", false},
 		{"valid viewer", "viewer", "pass", false},