Refactor power saving logic into display drivers and add ST7789 support

display/low_level_display_st7789.h

@@ -2,17 +2,7 @@
 #define LOW_LEVEL_DISPLAY_ST7789_H
 
 #include "low_level_display.h"
-
-// ST7789 configuration structure (similar to ST7796)
-struct st7789_config {
-    void* spi;           // SPI instance
-    int gpio_din;        // MOSI pin
-    int gpio_clk;        // Clock pin
-    int gpio_cs;         // Chip select pin
-    int gpio_dc;         // Data/Command pin
-    int gpio_rst;        // Reset pin
-    int gpio_bl;         // Backlight pin
-};
+#include "st7789.h"
 
 class LowLevelDisplayST7789 : public LowLevelDisplay {
 private:
@@ -42,8 +32,22 @@ public:
     // Backlight control
     void set_backlight(bool on) override;
     
+    // Brightness control
+    void set_brightness(uint8_t brightness) override;
+    uint8_t get_brightness() const override;
+
     // Orientation control
     void set_rotation(uint8_t rotation) override;
+
+    // Power saving hooks
+    void on_idle_2min() override;
+    void on_idle_10min() override;
+    void on_user_interaction() override;
+
+private:
+    uint8_t saved_brightness = 100;
+    bool is_dimmed = false;
+    bool is_sleeping = false;
 };
 
 #endif // LOW_LEVEL_DISPLAY_ST7789_H