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

scripts/release_build.sh

@@ -47,7 +47,7 @@ PREVIOUS="$(git -C "$SRC" describe --tags --abbrev=0 "$VERSION^" 2>/dev/null ||
     echo
     echo "## Files"
     echo
-    echo "- \`$NAME.ota\`: the signed Update File. Copy it to \`/updates\` on the SD card and install it from Settings > Firmware or the Storage App, or push it over Wi-Fi with \`scripts/ota_push.py\`."
+    echo "- \`$NAME.ota\`: the signed Update File. Copy it to \`/updates\` on the SD card and install it from Settings > System > Firmware or the Storage App, or push it over Wi-Fi with \`scripts/ota_push.py\`."
     echo "- \`$NAME-factory.bin\`: the whole flash image, for a first install over USB at offset 0."
     echo "- \`$NAME.elf.gz\`: the symbols, to decode a crash report from this build."
     echo "- \`SHA256SUMS\`: checksums of the three."