Remove dead code (#11082)

Removed:
- MessageStore::addFromPacket and addFromString, superseded by
  tryAddFromPacket
- GeoCoord rangeRadiansToMeters, distanceTo, bearingTo
- Router::rawSend, declared virtual with no override and no caller
- ContentHandler handleHotspot, handleFs, handleAdminSettings,
  handleAdminSettingsApply, handleDeleteFsContent and their commented
  route registrations, plus the now unreachable htmlDeleteDir and the
  handleUpdateFs declaration that had no definition
- ContentHelper replaceAll
- OnScreenKeyboardModule popup chain: showPopup, clearPopup, drawPopup,
  drawPopupOverlay and their state, unreachable since the frame based UI
  was replaced by baseUI
- DebugRenderer drawDebugInfoTrampoline, drawDebugInfoSettingsTrampoline
  and the orphaned drawFrameSettings
- NodeListRenderer calculateMaxScroll, drawColumns and a stale extern
  haveGlyphs declaration with no definition
- UIRenderer::haveGlyphs, Screen::blink,
  NotificationRenderer::showKeyboardMessagePopupWithTitle,
  VirtualKeyboard::getInputText
- InkHUD touchNavLeft, touchNavRight, Applet::getActiveNodeCount,
  ThreadedMessageApplet::saveMessagesToFlash
- TwoButton::setHandlerUp, TwoButtonExtended setHandlerUp,
  setJoystickDownHandlers, setJoystickUpHandlers
- CannedMessageModule LaunchRepeatDestination, isCharInputAllowed,
  hasMessages
- TrafficManagementModule resetStats, recordRouterHopPreserved,
  saturatingIncrement
- UnitConversions::MetersPerSecondToMilesPerHour
- EncryptedStorage getSessionRemainingSeconds
- BMI270Sensor::writeRegisters, GPS::hasFlow, FSCommon copyFile,
  SerialConsole consolePrintf, buzz playLongPressLeadUp,
  memGet displayPercentHeapFree

src/buzz/buzz.cpp

@@ -194,18 +194,6 @@ void playBoop()
     playTones(melody, sizeof(melody) / sizeof(ToneDuration));
 }
 
-void playLongPressLeadUp()
-{
-    // An ascending lead-up sequence for long press - builds anticipation
-    ToneDuration melody[] = {
-        {NOTE_C3, 100}, // Start low
-        {NOTE_E3, 100}, // Step up
-        {NOTE_G3, 100}, // Keep climbing
-        {NOTE_B3, 150}  // Peak with longer note for emphasis
-    };
-    playTones(melody, sizeof(melody) / sizeof(ToneDuration));
-}
-
 // Static state for progressive lead-up notes
 static int leadUpNoteIndex = 0;
 static const ToneDuration leadUpNotes[] = {

src/buzz/buzz.h

@@ -12,6 +12,5 @@ void play4ClickUp();
 void playBoop();
 void playChirp();
 void playClick();
-void playLongPressLeadUp();
 bool playNextLeadUpNote();  // Play the next note in the lead-up sequence
 void resetLeadUpSequence(); // Reset the lead-up sequence to start from beginning