feat(esp32-s3-lcd-43): add touch test harness and coordinate transformation

boards/esp32-s3-lcd-43/DisplayDriverGFX.h

@@ -18,6 +18,9 @@ public:
     int width() override;
     int height() override;
 
+    // Transform touch coordinates (handles rotated touch panels)
+    void transformTouch(int* x, int* y) override;
+
     // Dashboard tile mapping
     int dashboardTouch(int x, int y);
 
@@ -25,6 +28,9 @@ public:
     static DisplayDriverGFX& instance();
 
 private:
+    // Test harness: parse serial commands to inject synthetic touches
+    bool parseTestTouch(int* outX, int* outY, bool* outPressed);
+
     // Helper rendering functions
     void drawBoot(const ScreenState& state);
     void drawAlert(const ScreenState& state);
@@ -34,6 +40,9 @@ private:
     TouchEvent _lastTouch = { false, false, 0, 0, -1, -1 };
     unsigned long _pressStartMs = 0;
     bool _isHolding = false;
+    unsigned long _lastReleaseMs = 0;
+    bool _touchBounced = false;
+    bool _testMode = false;
 
     // Screen tracking
     ScreenID _lastScreen = ScreenID::BOOT;