feat: per-contact actions, device settings, a companion CLI and your contact's QR code

- Nodes: telemetry permissions per contact, reset path, share nearby
  (L1 options menu; L2 node card with "Can ask for" switches)
- Settings > Privacy: fixed position (typed in, from a waypoint, cleared)
  and the Bluetooth PIN; Settings > System: factory reset, asked twice
- Companion CLI (CMD_RUN_CLI_COMMAND 66 / RESP_CODE_CLI_REPLY 29, as
  upstream; FIRMWARE_VER_CODE 14): upstream's command names plus a key for
  every schema setting (get / set / keys)
- Screenshots move to 0x7E; tools/screenshot.py falls back to 66 / 29
- Your contact as a QR code (meshcore://contact/add): Status > System on
  ui-new, Settings > About on the L2; Nayuki's qrcodegen made header-only

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

examples/companion_radio/ui-new/UITask.h

@@ -508,6 +508,7 @@ public:
   // Settings changed through the schema (ui-core/SettingsSchema.h).
   void applyDisplayPrefs() override { applyBrightness(); _next_refresh = 0; }
   void applySoundPrefs() override;
+  bool cliCommand(const char* command, char* reply, int n) override;
   void setBuzzerVolumeLevel(uint8_t level);
   void applyTxPower();
   void applyPowerSave();   // hardware duty-cycle RX on/off from prefs