chore: enforce kafka-only stat path

docs/operations/jt808-daily-mileage-runbook.md

@@ -4,6 +4,8 @@
 
 The analytics app can calculate daily mileage from JT808 telemetry only. It consumes `vehicle.event.jt808.v1` and saves the current daily result into the common `vehicle-stat` metric repository.
 
+Only supported message backbone: Kafka.
+
 ## Storage
 
 Runtime state: none outside `vehicle_stat_metric`. There is no separate JT808 daily-mileage table. The derived value is stored as one `daily_mileage_km` metric row in the common JDBC/MySQL table `vehicle_stat_metric`; the local-day minimum and maximum GPS total mileage values are kept on that same row as calculation source columns.

docs/superpowers/plans/2026-06-30-kafka-streaming-mileage.md

@@ -6,6 +6,7 @@ Consume JT808 Kafka location events and write the derived daily mileage into the
 
 ## Current Design
 
+- Only supported message backbone: Kafka.
 - Source topic: `vehicle.event.jt808.v1`
 - Runtime app: `vehicle-analytics-app`
 - Runtime state: none outside `vehicle_stat_metric`
@@ -42,4 +43,4 @@ MYSQL_PASSWORD=<password>
 
 ## Notes
 
-Do not create or write a protocol-specific JT808 daily-mileage table. Do not add distance accumulation, integral calculation, Redis state, or memory state back into this path unless the mileage definition changes again.
+Do not create or write a protocol-specific JT808 daily-mileage table. Do not add MQ, distance accumulation, integral calculation, Redis state, or memory state back into this path unless the mileage definition changes again.

docs/target-architecture.md

@@ -5,6 +5,8 @@ The project should stay small at runtime: protocol apps ingest and publish,
 history consumes and indexes, analytics derives metrics, and business systems
 read through explicit APIs or Kafka.
 
+Only supported message backbone: Kafka.
+
 ## Active Scope
 
 Active production protocols: