LoRa Scanner: a MeshCore preset, and its packets read

- MeshCore joins the presets (EU/UK Narrow: 869.618 MHz, 62.5 kHz, SF8,
  CR 4/8, sync 0x12), after the Meshtastic ones so stored choices keep
  their number; `lora preset MeshCore` on the console
- lib/meshcore reads what MeshCore sends in clear: header, path, and a
  node's advert (name, kind, key, position)
- the list row, the details, a Capture's viewer and the console echo read
  a packet by the sync word it was received on
- the bandwidth is printed as 62.5, not 62

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

src/apps/lora_scanner_app.h

@@ -14,7 +14,7 @@
 namespace roro {
 
 // The LoRa Scanner (docs/milestones/M3.md). Sniffer: the packets the radio hears, newest first,
-// with the Meshtastic header read (Q96) and a hex dump on Enter; p picks the preset (Q95), c starts
+// with the Meshtastic or MeshCore header read (Q96) and a hex dump on Enter; p picks the preset (Q95), c starts
 // or stops a Capture (Q97). The radio listens while the App is open (Q100). Tab: Sweep, the band's
 // RSSI as bars with peak hold and a waterfall (Q98); it pauses the Sniffer while shown (Q99).
 class LoraScannerApp : public App {
@@ -40,7 +40,7 @@ class LoraScannerApp : public App {
     void showSweep(bool on);
     void openDetails();
     std::string timeOf(const RadioPacket& p) const;
-    bool meshtasticSettings() const;
+    lora::Protocol protocol() const;  // whose packets the radio is set for
     void say(const std::string& text);  // a line in the footer for a few seconds
 
     RadioService& radio_;