added loading screen

docs/claude/probe-readings.md

@@ -910,6 +910,30 @@ sets them to **7.5 and 250** before saving, so a key that never reached the file
 | `known:` after a rename | one row, under the new name | a rename that leaves the old file, so the chooser lists the same session twice |
 | `known:` for a settings-only configuration | a row, though `signals=0` | the listing filter treating "no signals yet" as "nobody configured this", which hides every host the form set up |
 
+## `[sources] loading`
+
+```
+[sources] picked 127.0.0.1:21077 multicast= interface= buffer=16 relative=0 capture=0 config=default note=''
+[sources] loading: title='Connecting to 127.0.0.1:21077' detail='planning the 16 MB sample buffer'
+[udpscope] CONFIG: 5 signals, publish=accumulate
+[sources] loading: closed
+```
+
+The loading window covering the gap from the chooser to the first frame of the real window. It is
+printed by any run that reaches the chooser, so `UDPSCOPE_PROBE_PICK_MS` reads the host leg and
+`UDPSCOPE_PROBE_WAVE=<path>` the file one (`title='Opening rt.npy' detail='reading the recording'`).
+
+| field | value it must read | the defect a wrong reading names |
+| --- | --- | --- |
+| `loading:` after `picked` | the address or basename just picked, and the buffer size | the window raised from the wrong place: before the chooser's answer it cannot name the wait, after the model it covers nothing |
+| its position in the log | **before** the `CONFIG:` or `waveform loaded:` lines | a window shown after the work it is meant to cover — the ten seconds of empty screen, unchanged |
+| `loading: closed` | **after** `CONFIG:`, i.e. once the real window is presented | a hide that runs earlier, which puts the screen back to empty for the frames the main window takes to map |
+| no `loading:` line at all | correct for a `--server` or `--open` run | only the path that *asked* gets one; a line here means every probe just changed path |
+
+`loading ui: loading.ui is missing an id this code reads` is the file-and-code mismatch the chooser's
+own check names, and like it the run continues: a loading window that cannot be built must not stop
+the app from opening.
+
 ## `[sources] prefs`
 
 ```