fix(box3): BOX-3 BSP + backlight

The project depended on espressif/esp-box (first-gen BOX: ST7789 +
TT21100 touch), which mis-initialises a real ESP32-S3-BOX-3 (ILI9341 +
GT911) and leaves the screen black. Switch the dependency to
espressif/esp-box-3 and use the generic bsp/esp-bsp.h header.

Also: the voice app started the display but never lit the backlight
("LCD backlight must be enabled separately" per the BSP). plip_ui_init
now calls bsp_display_brightness_init()/set(100) and uses a dark-blue
background with white text so the UI is actually visible.

Resolves clean (esp-box-3 3.2.0, esp_lcd_ili9341 2.0.2,
esp_lcd_touch_gt911 1.2.0); build green.

box3_voice/main/idf_component.yml

@@ -1,15 +1,10 @@
 dependencies:
-  espressif/esp-box:
+  # ESP32-S3-BOX-3 board support (ILI9341 LCD + GT911 touch). The original
+  # `espressif/esp-box` BSP targets the first-gen BOX (ST7789/TT21100) and
+  # leaves a BOX-3 screen black — this is the matching BSP.
+  espressif/esp-box-3:
     version: ">=1.2.0"
   espressif/esp-sr:
     version: ">=1.4.0"
-  espressif/esp_codec_dev:
-    # 1.3.x+ moved to driver_ng i2c, conflicting with esp-box 1.x legacy BSP.
-    # Pin to the last 1.2 release that still uses the legacy driver.
-    version: "1.2.0"
-  espressif/button:
-    # esp-box 1.x bsp uses the old button_config_t.custom_button_config API;
-    # button v3.x removed it. Pin to the last 2.x release for compat.
-    version: "~2.5.0"
   espressif/esp_websocket_client:
     version: ">=1.0.0"

box3_voice/main/plip_ui.c

@@ -9,7 +9,7 @@
 
 #include <string.h>
 
-#include "bsp/esp-box.h"
+#include "bsp/esp-bsp.h"
 #include "esp_log.h"
 #include "lvgl.h"
 
@@ -181,8 +181,14 @@ esp_err_t plip_ui_init(void)
         return ESP_FAIL;
     }
 
+    // The voice app starts the display but never lights the backlight — turn
+    // it on (and to full brightness) or the whole UI is invisible.
+    bsp_display_brightness_init();
+    bsp_display_brightness_set(100);
+
     lv_obj_t *scr = lv_screen_active();
-    lv_obj_set_style_bg_color(scr, lv_color_black(), 0);
+    lv_obj_set_style_bg_color(scr, lv_color_hex(0x101020), 0);
+    lv_obj_set_style_text_color(scr, lv_color_white(), 0);
 
     // Content area above the fixed bottom button.
     lv_obj_t *content = lv_obj_create(scr);