feat: LVGL 9.5 upgrade, FTP server, premium AMOLED UI

- Upgraded LVGL from 8.4 to 9.5.0 (new display/input API)
- Rewrote DisplayManager for LVGL 9 (lv_display_create, tick callback)
- New lv_conf.h for v9.5 with optimized widget selection
- Premium dark AMOLED UI with gradient panels, status dots, storage bar
- Backend: Wi-Fi from SD JSON, NTP Vienna, SimpleFTPServer on SD_MMC
- Removed 6 unused sensor libs, added ArduinoJson + SimpleFTPServer
- Build: 19% RAM, 4.6% Flash — verified compilation success

lib/kodedot_bsp/include/kodedot/display_manager.h

@@ -7,72 +7,37 @@
 #include <bb_captouch.h>
 
 /**
- * @brief High-level manager that initializes and wires up the display, LVGL, and touch input.
- *
- * Responsibilities:
- * - Bring up the panel using Arduino_GFX
- * - Allocate LVGL draw buffers (prefer PSRAM, fallback to SRAM)
- * - Register LVGL display and input drivers
- * - Provide simple helpers for brightness and touch reading
+ * @brief High-level manager for display, LVGL 9 and touch on Kode Dot.
  */
 class DisplayManager {
 private:
-    // Hardware interfaces
     Arduino_DataBus *bus;
-    Arduino_CO5300 *gfx;
-    BBCapTouch bbct;
-    
-    // LVGL draw buffer and driver handles
-    lv_disp_draw_buf_t draw_buf;
-    lv_color_t *buf;
-    lv_color_t *buf2;
-    lv_disp_drv_t disp_drv;
-    
-    // Static callbacks required by LVGL
-    static void disp_flush_callback(lv_disp_drv_t *disp, const lv_area_t *area, lv_color_t *color_p);
-    static void touchpad_read_callback(lv_indev_drv_t *indev_drv, lv_indev_data_t *data);
-    
-    // Singleton-like back-reference used by static callbacks
-    static DisplayManager* instance;
+    Arduino_CO5300  *gfx;
+    BBCapTouch       bbct;
+
+    // LVGL 9 handles
+    lv_display_t *lv_disp;
+    lv_indev_t   *lv_touch;
+    uint8_t      *buf1;
+    uint8_t      *buf2;
+
+    // Static callbacks
+    static void disp_flush_cb(lv_display_t *disp, const lv_area_t *area, uint8_t *px_map);
+    static void touch_read_cb(lv_indev_t *indev, lv_indev_data_t *data);
+
+    static DisplayManager *instance;
 
 public:
     DisplayManager();
     ~DisplayManager();
-    
-    /**
-     * @brief Fully initialize display, LVGL, and touch.
-     * @return true on success, false otherwise
-     */
+
     bool init();
-    
-    /**
-     * @brief Get the underlying Arduino_GFX panel instance.
-     */
-    Arduino_CO5300* getGfx() { return gfx; }
-    
-    /**
-     * @brief Get the touch controller instance.
-     */
-    BBCapTouch* getTouch() { return &bbct; }
-    
-    /**
-     * @brief Pump LVGL timers and tick. Call frequently in loop().
-     */
     void update();
-    
-    /**
-     * @brief Set backlight brightness.
-     * @param brightness Range 0-255
-     */
     void setBrightness(uint8_t brightness);
-    
-    /**
-     * @brief Read current touch coordinates.
-     * @param x Output X coordinate
-     * @param y Output Y coordinate
-     * @return true if there is an active touch
-     */
     bool getTouchCoordinates(int16_t &x, int16_t &y);
+
+    Arduino_CO5300 *getGfx() { return gfx; }
+    BBCapTouch     *getTouch() { return &bbct; }
 };