docs: state that Locate's readouts decay instead of freezing (TRA-1123, hold for v1.5.0)

docs/app-tour/locate.md

@@ -16,7 +16,24 @@ description: Find a specific item by walking the area with a handheld reader.
 
 ## What this page does
 
-Locate is a proximity finder for a single tag. You paste a **Tag EPC Identifier** into the field, then either press the on-screen **Start** button (enabled once a reader is connected) or press and hold the physical trigger — both begin the same search. A semicircular **Signal Strength** gauge, scaled in dBm from -100 to -20 and banded red-to-green, updates in real time as you walk: stronger signal means the tag is closer. A **Statistics** panel tracks Current / Average (1s) / Peak readings, an update rate in Hz, and an overall Status (Idle / Searching), and a rolling 10-second signal history sits alongside it once a search is running. An **Audio Feedback** toggle, on by default, plays a tone whose pitch rises with signal strength so you don't need to look at the screen while hunting.
+Locate is a proximity finder for a single tag. You paste a **Tag EPC Identifier** into the field, then either press the on-screen **Start** button (enabled once a reader is connected) or press and hold the physical trigger — both begin the same search. A semicircular **Signal Strength** gauge, scaled in dBm from -100 to -20 and banded red-to-green, updates in real time as you walk: stronger signal means the tag is closer. A **Statistics** panel and a rolling signal history sit below it, and an **Audio Feedback** toggle, on by default, plays a tone whose pitch rises with signal strength so you don't need to look at the screen while hunting.
+
+### Reading the signal
+
+Every live readout follows the read stream rather than the search itself, so a value on screen means the tag is being heard **right now**. When reads stop — because you have walked out of range, the tag is not there, or you retargeted to a different EPC — they fall back rather than holding the last value.
+
+| Readout                     | Shows                               | When reads stop                                   |
+| --------------------------- | ----------------------------------- | ------------------------------------------------- |
+| **Signal Strength** gauge   | Current strength in dBm             | **No signal**                                     |
+| **Current**                 | Most recent reading                 | **No signal**                                     |
+| **Average (1s)**            | Mean over the last second           | **No signal**                                     |
+| **Peak**                    | Strongest reading of this search    | **No signal**                                     |
+| **Update Rate**             | Readings per second                 | **0 Hz**                                          |
+| Signal history              | Rolling 10-second trace             | Disappears                                        |
+| **Status**                  | Whether a search is running         | Stays **Searching** until you stop                |
+| **Last search - Peak RSSI** | Best reading of the finished search | Retained — this line is history, not a live value |
+
+Two of those are deliberate exceptions. **Status** reports the search, not the signal, so it keeps saying **Searching** even when nothing is coming back — that is how you tell "still looking" from "found nothing yet". And **Last search - Peak RSSI**, under the EPC field, is the one place a finished search's best reading is kept on purpose.
 
 ## How it fits in the app