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

lib/lora/src/scan_presets.cpp

@@ -0,0 +1,34 @@
+#include "scan_presets.h"
+
+#include <cctype>
+
+#include "meshcore_packet.h"
+#include "meshtastic_presets.h"
+
+namespace roro::lora {
+
+size_t scanPresetCount() { return meshtastic::kEu868PresetCount + 1; }
+
+ScanPreset scanPreset(size_t i) {
+    if (i < meshtastic::kEu868PresetCount) {
+        const meshtastic::Preset& p = meshtastic::kEu868Presets[i];
+        return {p.name, meshtastic::eu868FrequencyHz(p), p.bwKHz, p.sf, p.cr, meshtastic::kSyncWord, meshtastic::kPreambleLength, Protocol::Meshtastic};
+    }
+    return {meshcore::kPresetName, meshcore::kEuNarrowHz, meshcore::kEuNarrowBwKHz, meshcore::kEuNarrowSf, meshcore::kEuNarrowCr,
+            meshcore::kSyncWord, meshcore::kPreambleLength, Protocol::MeshCore};
+}
+
+bool findScanPreset(const char* name, ScanPreset& out) {
+    for (size_t i = 0; i < scanPresetCount(); ++i) {
+        ScanPreset p = scanPreset(i);
+        const char *a = p.name, *b = name;
+        while (*a && *b && std::tolower(static_cast<unsigned char>(*a)) == std::tolower(static_cast<unsigned char>(*b))) ++a, ++b;
+        if (!*a && !*b) {
+            out = p;
+            return true;
+        }
+    }
+    return false;
+}
+
+}  // namespace roro::lora