Reduce touch overhead and cap frame rate at 24 FPS

lib/input_manager.h

@@ -97,6 +97,8 @@ public:
 private:
     LowLevelTouch* touch;
     const GameConfig* config;
+    // Last time we sampled touch over I2C while a touch session is active.
+    uint32_t last_touch_sample_ms = 0;
     // Consecutive touch_count==0 samples while a touch session is active.
     // Used to suppress false TOUCH_UP events from transient touch controller jitter.
     uint8_t no_touch_samples = 0;