Measure refresh latency independently and retain intended result selection

docs/PERFORMANCE.md

@@ -83,6 +83,14 @@ model loading must not be silently included in a warm-query claim.
 
 ## Reproducible performance validation
 
+Automatic filesystem refreshes start a new frontend measurement at the refresh
+event. `trigger: "filesystem_refresh"` distinguishes them from user searches;
+`SHOWN` and `latest_displayed_ms` exclude time spent idle before that event.
+`original_input` retains a fixed-size snapshot of the original debounce and
+display timings. Refreshes do not replay previous attempts or append ancestor
+traces. A refresh before the first response leaves that original response timing
+null rather than inventing a first-input measurement.
+
 Record build profile, CPU/device and thread budget, VM/host resources, corpus and
 active generation, filters, cold/warm state, concurrent indexing and setup costs.
 Use multiple queries and p50/p95 distributions; retain raw reports. Compare basic