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

platformio.ini

@@ -56,7 +56,7 @@ upload_command = esptool --chip esp32s3 --port ${UPLOAD_PORT} --baud ${UPLOAD_SP
 ; Libraries
 lib_deps =
   moononournation/GFX Library for Arduino @ ^1.6.0
-  lvgl/lvgl @ ^8.3.9
+  lvgl/lvgl @ ^9
   adafruit/Adafruit NeoPixel
   https://github.com/RobTillaart/TCA9555.git#0.4.3
   https://github.com/bitbank2/bb_captouch.git