fix: with_sender buffer too small and FS_LINE_H mismatch

- with_sender[160] could hold only ~160 chars but node_name(32) +
  expanded(200) needs up to 234; snprintf would silently truncate
  the UI display entry. Increased to 240.
- FS_LINE_H was 9 but Adafruit 5x7 font line height is 8, wasting
  1px per line and showing 5 lines instead of 6.

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

examples/companion_radio/MyMeshBot.h

@@ -70,7 +70,7 @@ void MyMesh::tryBotReplyChannel(uint8_t channel_idx, const char* text) {
     _bot_last_reply_ms = millis();
 #ifdef DISPLAY_CLASS
     if (_ui) {
-      char with_sender[160];
+      char with_sender[240];  // node_name(32) + ": "(2) + expanded(200) + margin
       snprintf(with_sender, sizeof(with_sender), "%s: %s", _prefs.node_name, expanded);
       _ui->addChannelMsg(channel_idx, with_sender);
     }