fix(swagger): restore apikey security definition with Bearer usage description

cmd/server/main.go

@@ -46,11 +46,15 @@ import (
 // @host            localhost:8080
 // @BasePath        /
 
-// @securityDefinitions.bearer AdminAuth
-// @description Admin token for management API access
+// @securityDefinitions.apikey AdminAuth
+// @in header
+// @name Authorization
+// @description Type "Bearer" followed by a space and the admin token. Example: Bearer admin123
 
-// @securityDefinitions.bearer MasterAuth
-// @description Master key for tenant API access
+// @securityDefinitions.apikey MasterAuth
+// @in header
+// @name Authorization
+// @description Type "Bearer" followed by a space and the master key. Example: Bearer sk-xxx
 
 func fatal(logger *slog.Logger, msg string, args ...any) {
 	logger.Error(msg, args...)