display_gif_embedded: port to LVGL 9.6.0 (20.6 -> 23.4 fps)

- lvgl/lvgl@9.6.0 via lib_deps, lv_conf.h from the 9.6 template
- scr_st77916.h: lv_display/lv_indev API, RGB565 byte swap in flush,
  lv_tick_set_cb
- FPS counter via display refresh events
- loligod.c: lv_image_dsc_t descriptor

GIF now plays at its own frame rate; decode time halved by LVGL 9.6's
AnimatedGIF decoder.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

10-OBD-Display-2024/display_gif_embedded/platformio.ini

@@ -23,8 +23,10 @@ build_flags =
     -DLV_CONF_INCLUDE_SIMPLE
     -Iinclude
 
-; vendor-bundled libraries: ESP32_Display_Panel 0.1.4, ESP32_IO_Expander 0.0.2, lvgl 8.3.11
+; vendor-bundled libraries: ESP32_Display_Panel 0.1.4, ESP32_IO_Expander 0.0.2
+; (the vendor folder also has lvgl 8.3.11 - ignored here, this project uses LVGL 9 from lib_deps)
 lib_extra_dirs = ../../2-Program Example/Demo_Arduino/library
+lib_deps = lvgl/lvgl@9.6.0
 
 upload_port = COM21
 monitor_port = COM21