Fix 3.5 KY-009: backlight GPIO27 and G on GPIO21.

Align cyd_35r with CYD_PROJECT_GUIDE (ST7796/GT911), export flashable firmware/cyd_35r.

Co-authored-by: Cursor <cursoragent@cursor.com>

platformio.ini

@@ -1,5 +1,6 @@
-; CYD ESP32-2432S028 — KY-009 RGB LED (R=22, G=27, B=4) + SoftSPI 触控 + LVGL
-; 触控/屏配置参考 tftest / hw269test
+; KY-009 RGB + LVGL
+; 2.8" [env:cyd]     R22 G27 B4  BL21 SoftSPI
+; 3.5" [env:cyd_35r] R22 G21 B4  BL27 GT911  — see ../CYD_PROJECT_GUIDE.md
 [env:cyd]
 platform = espressif32
 board = esp32dev
@@ -55,19 +56,26 @@ build_flags =
 
 extra_scripts = pre:copy_lv_conf.py
 
-; Optional 3.5" CYD ESP32-3248S035 (ST7796 resistive). Default remains [env:cyd].
+; Optional 3.5" CYD ESP32-3248S035C (ST7796 + GT911 capacitive). Default [env:cyd].
 ; Build: pio run -e cyd_35r
+; Keep TOUCH_CS=-1 — GPIO33 is GT911 SDA, not resistive touch CS.
+; TFT_BL=GPIO27 (not 21 — 21 is GT911 INT / KY009 G). See ../CYD_PROJECT_GUIDE.md
 [env:cyd_35r]
 extends = env:cyd
+build_unflags =
+  -DILI9341_2_DRIVER=1
+  -DTFT_WIDTH=240
+  -DTFT_HEIGHT=320
+  -DTFT_BL=21
+  -DLV_MEM_SIZE=49152
 build_flags =
   ${env:cyd.build_flags}
-  -UILI9341_2_DRIVER
   -DST7796_DRIVER=1
-  -UTFT_WIDTH
-  -UTFT_HEIGHT
   -DTFT_WIDTH=320
   -DTFT_HEIGHT=480
-  -UTFT_BL
   -DTFT_BL=27
   -DCYD_BOARD_3248S035=1
-
+  -DUSE_HSPI_PORT
+  -DSUPPORT_TRANSACTIONS
+  -DTFT_RGB_ORDER=TFT_BGR
+  -DLV_MEM_SIZE=32768