feat(platform): expose no-data vehicles

vehicle-data-platform/docs/product-spec.md

@@ -28,6 +28,8 @@ Vehicle service lists and dashboard previews should label protocol coverage as `
 
 Dashboard and vehicle-list summary cards should expose both `单源车辆` and `多源车辆`. Single-source vehicles are operationally important because they cannot be cross-checked across sources, so they must be one-click filter targets rather than hidden behind the generic coverage filter.
 
+`暂无来源车辆` is also a first-class governance entry. It represents bound vehicles that have no current GB32960, JT808, or Yutong MQTT source evidence, and should route directly to the `no_data` vehicle service filter.
+
 ## Interaction Rules
 
 - Tables are the default data surface.