Settings: add Home Pages visibility control

New "Home Pages" section in Settings lets the user toggle which pages
appear in the home screen carousel. Settings and Messages are always
shown; Clock, Recent, Radio, Bluetooth, Advert, GPS, Sensors, Tools
and Shutdown can each be hidden individually.

- NodePrefs: home_pages_mask uint16_t (bit per page, 0=all visible)
- HomeScreen: isPageVisible/navPage skip hidden pages; dots indicator
  counts only visible pages; enforces visible page on re-entry
- SettingsScreen: SECTION_HOME_PAGES with per-page ON/OFF toggles
- DataStore: persisted at offset 1598
- Default: all pages visible (0x01FF)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

examples/companion_radio/NodePrefs.h

@@ -48,4 +48,5 @@ struct NodePrefs {  // persisted to file
   uint8_t  ringtone_bpm_idx;   // index into {60,90,120,150,180}
   uint8_t  ringtone_len;        // number of notes in custom ringtone (0 = use default)
   uint8_t  ringtone_notes[32]; // packed: bits0-2=pitch, bits3-4=octave-4, bits5-6=dur_idx
+  uint16_t home_pages_mask;    // bitmask of visible home pages (bit0=Clock..bit8=Shutdown); 0=all visible
 };