fix(platform): harden queries and batch vehicle search

vehicle-data-platform/docs/frontend-production-readiness.md

@@ -9,6 +9,7 @@ This document records verified risks, the production controls that address them,
 | Risk | User-visible failure | Control | Evidence gate |
 | --- | --- | --- | --- |
 | A stale lazy route asset disappears during release | Navigation leaves the content area blank | Preserve the previous build's original hashed assets for one generation; isolate every route with a recoverable error boundary and one-shot reload | Request an old route asset after the symlink switch; navigate through every primary route without a blank shell |
+| A pasted batch search temporarily shows the previous fleet | Operators may mistake stale vehicles for batch matches | Hide placeholder rows while `keywords` is changing; report matched and missing plates after the request resolves | Paste newline/comma-separated plates with a duplicate and an unknown plate; verify exact results and missing-count feedback |
 | A route is first fetched only after click | Slow transitions and a longer loading flash | Deduplicated route import cache plus pointer, focus and pointer-down preload | Route module unit tests and rendered navigation loop |
 | Rapid map pans retain large query payloads | Heap growth and eventual interaction jank | Consume React Query `AbortSignal` and immediately garbage-collect inactive map viewport queries | Query-cache churn test keeps exactly one map payload after repeated viewport changes |
 | Superseded monitor requests continue in the background | Wasted server traffic and stale responses | Pass request cancellation signals through the API client | API client signal test and browser network/console smoke |
@@ -26,6 +27,12 @@ The navigation and progressive-loading direction follows mature observability sy
 4. Reduce the shared CSS and Semi UI payload; preserve ExcelJS as an action-only dynamic import and consider moving large workbook generation off the main thread.
 5. Add an automated release smoke that reads the previous `.release-assets` manifest and asserts every listed compatibility asset returns HTTP 200.
 
+## 2026-07-15: query memory and vehicle-count semantics
+
+Production reconciliation proved that the three visible vehicle counts represent different populations rather than a data loss: 1,035 service identities equal 1,024 bound master vehicles plus 11 realtime identities awaiting binding; 738 vehicles currently have a realtime location row and can enter the global-monitor map. The UI must name these populations explicitly instead of presenting them as interchangeable totals.
+
+High-volume history rows, aggregated series, track playback and daily-mileage matrices consume the request `AbortSignal` and use zero inactive-cache retention. Small vehicle-option and summary results retain only a bounded 30–60 second cache. This preserves responsive repeated lookups without retaining multiple large arbitrary date-window payloads after their observer is gone.
+
 ## Release evidence template
 
 - Commit and release identifier