chore: post-sync cleanup and clang-format

- Remove stale Lyra3CoversTheme.h (functionality merged into LyraTheme)
- Fix UITheme.cpp to use LyraTheme for LYRA_3_COVERS theme variant
- Update open-x4-sdk submodule to 91e7e2b (drawImageTransparent support)
- Run clang-format on all source files

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/hal/HalDisplay.cpp

@@ -38,8 +38,8 @@ void HalDisplay::displayBuffer(HalDisplay::RefreshMode mode, bool turnOffScreen)
 }
 
 // EXPERIMENTAL: Display only a rectangular region
-void HalDisplay::displayWindow(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
-                               HalDisplay::RefreshMode mode, bool turnOffScreen) {
+void HalDisplay::displayWindow(uint16_t x, uint16_t y, uint16_t w, uint16_t h, HalDisplay::RefreshMode mode,
+                               bool turnOffScreen) {
   (void)mode;  // EInkDisplay::displayWindow does not take mode yet
   einkDisplay.displayWindow(x, y, w, h, turnOffScreen);
 }