docs: simplify jt808 mileage runtime state

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

@@ -6,7 +6,7 @@ The analytics app can calculate daily mileage from JT808 telemetry only. It cons
 
 ## Storage
 
-There is no separate JT808 daily-mileage table and no Redis mileage state. 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.
+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.
 
 The JT808 daily-mileage value is calculated from the GPS total mileage reported in location additional information:
 
@@ -29,4 +29,4 @@ MYSQL_USERNAME=<user>
 MYSQL_PASSWORD=<password>
 ```
 
-Algorithm defaults use the Asia/Shanghai daily boundary. Restart recovery reads the same `daily_mileage_km` metric row, so no separate mileage state store is required.
+Algorithm defaults use the Asia/Shanghai daily boundary. Restart recovery reads the same `daily_mileage_km` metric row.

docs/target-architecture.md

@@ -32,8 +32,7 @@ is explicitly deployed.
 - Store complete raw payload metadata and parsed JSON in TDengine `raw_frames`.
 - Store query-friendly location rows separately from raw payload JSON.
 - Keep derived statistics in metric tables, not protocol-specific daily tables.
-- Use Redis only for hot state or streaming calculation state that can be
+- Use Redis only for optional latest-state APIs that can be rebuilt from Kafka.
-  rebuilt from Kafka.
 - Keep optional compatibility modules outside the production hot path.
 
 ## Non-Goals
@@ -133,9 +132,8 @@ calculation_method = JT808_TOTAL_MILEAGE_DIFF
   mileage used for the subtraction stay on the same metric row as calculation
   source columns.
 
-There is no JT808-specific daily mileage table and no in-memory production
+Runtime state: none outside `vehicle_stat_metric`. There is no JT808-specific
-state-store mode. Restart recovery reads the same metric row, so it does not
+daily mileage table. Restart recovery reads the same metric row.
-require a separate Redis mileage state.
 
 ### Latest State
 
@@ -196,6 +194,5 @@ flowchart LR
 - Location queries page over compact rows and reference raw records instead of
   duplicating full raw JSON.
 - JT808 daily mileage is stored only in `vehicle_stat_metric`.
-- Runtime state needed for 808 mileage is also in `vehicle_stat_metric`, with no
+- Runtime state needed for 808 mileage is also in `vehicle_stat_metric`.
-  Redis or production memory state-store mode.
 - Build validation covers the active modules and their composition tests.

modules/services/vehicle-stat-service/src/test/java/com/lingniu/ingest/vehiclestat/VehicleStatRepositoryContractTest.java

@@ -35,6 +35,31 @@ class VehicleStatRepositoryContractTest {
                 .doesNotContain("speed integral");
     }
 
+    @Test
+    void targetArchitectureDocumentsMetricTableAsOnlyJt808MileageRuntimeState() throws IOException {
+        String architecture = Files.readString(repositoryRoot().resolve("docs/target-architecture.md"));
+
+        assertThat(architecture)
+                .contains("Runtime state: none outside `vehicle_stat_metric`")
+                .contains("Restart recovery reads the same metric row")
+                .contains("JT808 daily mileage is stored only in `vehicle_stat_metric`")
+                .doesNotContain("state-store")
+                .doesNotContain("Redis mileage state")
+                .doesNotContain("production memory");
+    }
+
+    @Test
+    void jt808MileageRunbookDocumentsMetricTableAsOnlyRuntimeState() throws IOException {
+        String runbook = Files.readString(repositoryRoot()
+                .resolve("docs/operations/jt808-daily-mileage-runbook.md"));
+
+        assertThat(runbook)
+                .contains("Runtime state: none outside `vehicle_stat_metric`")
+                .contains("Restart recovery reads the same `daily_mileage_km` metric row")
+                .doesNotContain("Redis mileage state")
+                .doesNotContain("state-store");
+    }
+
     private static Path repositoryRoot() {
         Path path = Path.of("").toAbsolutePath();
         while (path != null && !Files.exists(path.resolve("docs/superpowers/plans"))) {