Serial monitor redesign: Test box button, InfluxDB row in the checklist

- Test box: restart + start-up capture + online InfluxDB check (data newer
  than the restart), with a status strip; checklist and findings are the
  main view, live log / guided troubleshooting / box details are tabs,
  rarely used actions in a More menu
- light palette on all systems (macOS dark mode made the colours unreadable)
- new rule influx.invalid_value: -inf from a silent microphone makes
  InfluxDB reject every upload (HTTP 400); guide end names it
- exclusive serial port on macOS/Linux: two tool windows no longer split
  the log between them
- InfluxDB check: `since` filter, neutral wording when nothing new arrives

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/CHANGES-v0.10.md

@@ -24,3 +24,18 @@
   The token is never written to the session log or the service report.
 - macOS: Connect no longer restarts the box (pyserial dropped DTR before RTS, passing through the
   USB-Serial-JTAG reset state). Windows unchanged.
+- **Serial monitor redesigned.** One green **Test box** button: restarts the box, records the start-up and
+  then checks InfluxDB online (data must be newer than the restart), about 4 minutes. A status strip shows
+  what the test is doing and its result. The test checklist (start-up steps + the new row
+  "Sensor data in InfluxDB (online check)") and the findings are the main view; the live log, guided
+  troubleshooting and box details (LED, firmware, self-report) are tabs on the right. Rarely used actions
+  moved to **More**.
+- Light colour scheme on every system: with macOS dark mode the status colours were unreadable.
+  Larger log font on macOS.
+- New finding **Box sends an invalid value (-inf/nan) - InfluxDB rejects all its data**: a silent microphone
+  makes the firmware upload `dbfs=-inf,db=-inf`; InfluxDB then refuses the whole upload (HTTP 400), so neither
+  the status nor the sensor data arrive (box A4:CB:8F:C9:47:3C). The InfluxDB check names it as the cause.
+- The serial port is opened exclusively on macOS/Linux: a second tool window no longer steals half of the
+  log lines; it reports that the port is in use.
+- Start-up step "Data uploaded to InfluxDB" renamed "Upload accepted by InfluxDB (box log)" - it comes
+  from the box's own log, the online row checks the database.