Add touch-to-logical coordinate mapping for UI

Implements tapToLogical() to convert normalized touch coordinates to orientation-aware logical screen coordinates. Adds TouchRegistry hit testing for interactive UI elements and header back button. Touch gestures now work correctly across all screen orientations (Portrait, Landscape, etc.) by inverting the rotateCoordinates transform.

src/activities/reader/EpubReaderBookmarksActivity.cpp

@@ -103,7 +103,10 @@ void EpubReaderBookmarksActivity::loop() {
     }
   }
 
-  if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {  // Open
+  int tappedId = -1;
+  const bool tapped = (confirmingDelete < DELETE_MODE_DISPLAY) && mappedInput.wasItemTapped(tappedId);
+  if (tapped && tappedId >= 0 && tappedId < static_cast<int>(bookmarks.size())) selectorIndex = tappedId;
+  if (tapped || mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {  // Open
     if (bookmarks.empty()) {
       return;
     }