Under the hood; finishes the main page code split.
Changed
- Main page code split (final round): the last large inline
<script>in index.html — the mode-switch core, SDR device handling, pager, and APRS — moves into four files understatic/js/modes/(core-mode-switch.js, sdr-device.js, pager.js, aprs-spa.js), loaded in the same order as before. index.html goes from 7,643 to 4,014 lines and is now almost entirely markup plus linked scripts. Content moved unchanged (only de-indented; verified byte-for-byte against the original block). Two template-embedded values (the initial device list and the satellite-dashboard version fallback) now read fromwindow.INTERCEPT_INITIAL_DEVICES/window.INTERCEPT_VERSION. No behaviour change; verified by the browser smoke test.
Also adds an internal written plan (plans/aprs-meshtastic-dashboard-migration.md) for moving APRS and Meshtastic to dedicated dashboard pages.