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- MessageStore::addFromPacket and addFromString, superseded by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/memGet.cpp

@@ -9,7 +9,6 @@
  */
 #include "memGet.h"
 #include "configuration.h"
-#include "memory/MemAudit.h"
 
 #if defined(MESHTASTIC_DYNAMIC_SBRK_HEAP)
 #include <malloc.h>
@@ -108,16 +107,3 @@ uint32_t MemGet::getPsramSize()
     return 0;
 #endif
 }
-
-void displayPercentHeapFree()
-{
-    uint32_t freeHeap = memGet.getFreeHeap();
-    uint32_t totalHeap = memGet.getHeapSize();
-    if (totalHeap == 0 || totalHeap == UINT32_MAX) {
-        LOG_INFO("Heap size unavailable");
-        return;
-    }
-    int percent = (int)((freeHeap * 100) / totalHeap);
-    LOG_INFO("Heap free: %d%% (%u/%u bytes)", percent, freeHeap, totalHeap);
-    memaudit::logBreakdown("heap"); // per-subsystem breakdown rides along with the periodic heap log
-}