Fix 3.5C pins per CYD_PROJECT_GUIDE: BL=27, LD2420 TX=GPIO4, GT911 INT as INPUT.

Black-screen cause was TFT_BL=21; archive flashable firmware/cyd_35r.

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

platformio.ini

@@ -1,6 +1,6 @@
-; CYD ESP32-2432S028R <EFBFBD><EFBFBD>?LVGL LD2420 毫米波雷达仪表盘
-; LD2420 OT1 -> GPIO22 (ESP RX), LD2420 RX -> GPIO27 (ESP TX)
-
+; CYD ESP32-2432S028R — LVGL LD2420 mmWave radar dashboard
+; LD2420 OT1 -> GPIO22 (ESP RX); module RX -> GPIO27 (2.8 ESP TX) / GPIO4 (3.5 ESP TX)
+; See ../CYD_PROJECT_GUIDE.md — 3.5 BL=27, GT911 INT=21 (not BL).
 [platformio]
 default_envs = cyd_28r
 
@@ -45,12 +45,12 @@ build_flags =
   -D LV_CONF_INCLUDE_SIMPLE=1
   -I include
 
-; 标准 CYD 2.8" 电阻<E794B5><EFBFBD>?(ILI9341)
+; 标准 CYD 2.8" 电阻<E794B5>?(ILI9341)
 [env:cyd_28r]
 build_flags =
   ${env.build_flags}
 
-; 颜色反相版本（若画面色偏/发白可改用此环境<E78EAF><EFBFBD>?
+; 颜色反相版本（若画面色偏/发白可改用此环境<E78EAF>?
 [env:cyd_28r_inv]
 build_flags =
   ${env.build_flags}
@@ -65,18 +65,27 @@ build_flags =
   -D TFT_RGB_ORDER=TFT_BGR
   -D TFT_INVERSION_ON=1
 
-; Optional 3.5" CYD ESP32-3248S035 (ST7796 resistive). Default remains cyd_28r.
+; Optional 3.5" CYD ESP32-3248S035C (ST7796 + GT911 capacitive). Default remains cyd_28r.
 ; 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). LD2420 ESP TX -> GPIO4 (27=BL).
 [env:cyd_35r]
+lib_deps =
+  lvgl/lvgl@9.2.2
+  bodmer/TFT_eSPI@2.5.43
 build_flags =
   ${env.build_flags}
-  -U ILI9341_2_DRIVER
-  -D ST7796_DRIVER=1
-  -U TFT_WIDTH
-  -U TFT_HEIGHT
-  -D TFT_WIDTH=320
-  -D TFT_HEIGHT=480
-  -U TFT_BL
-  -D TFT_BL=27
-  -D CYD_BOARD_3248S035=1
+  -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
+  -DSUPPORT_TRANSACTIONS
+  -DTFT_RGB_ORDER=TFT_BGR
+  -ULV_MEM_SIZE
+  -DLV_MEM_SIZE=32768