Settings: its rows in five groups

Settings had grown to 21 rows in one list. It opens on five groups (This
device, Display, GNSS and radio, Network, System); Enter opens one, Back
returns to the groups, and Back from the groups leaves Settings.

SettingsMenu holds the groups and which one is open (host-tested: every
setting is in exactly one group). The guide, the how-tos, the README,
the scripts' messages and the firmware's own name the new paths, such as
"Settings > System > Firmware".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0162FokPdvY2KsS4NBfwyWPk

site/content/guide/lora-scanner.md

@@ -63,7 +63,7 @@ A capture records packets into a **pcap** file with LoRaTap headers in `/capture
 
 ## The GNSS receiver raises the noise
 
-The GNSS receiver on the same Cap makes the radio's noise floor about **8 dB** worse while it runs. **Settings → Pause GNSS for LoRa** (off by default) puts the receiver on standby while the radio listens, except while a Track is being recorded.
+The GNSS receiver on the same Cap makes the radio's noise floor about **8 dB** worse while it runs. **Settings → GNSS and radio → Pause GNSS for LoRa** (off by default) puts the receiver on standby while the radio listens, except while a Track is being recorded.
 
 ## The keys, as the device lists them