Add CYD 3.5C build: I2S on 22/21/35 with GT911 poll-only touch.

Export firmware/cyd_35r and document GPIO21 shared with GT911 INT.

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

firmware/cyd_35r/VERSION.txt

@@ -0,0 +1,17 @@
+name: CYD inmp441test (cyd_35r)
+git: 78658e3
+date: 2026-10-27
+board: ESP32-3248S035 (ST7796 + GT911)
+inmp441: WS=GPIO22 SCK=GPIO21 SD=GPIO35
+tft_bl: GPIO27
+flash_size: 4MB
+offsets:
+  0x1000  bootloader.bin
+  0x8000  partitions.bin
+  0xe000  boot_app0.bin
+  0x10000 firmware.bin
+sha256:
+  bootloader.bin  3D234A7471F67B013686DABD4DEE7C1FA915C9928463616A94BC9297ACF1ABF8
+  boot_app0.bin   F94C5D786A7A8FAB06AC5D10E33BF37711A6697636DC037559EA19CC410A17F0
+  firmware.bin    54A9F577980859E69E06F28982A632245AB3D67C99893C8B6996C510E25DC205
+  partitions.bin  0A8B5720E7B77FF11F1462458C3A509DEE79224E5279898F26D6A2E3AE0517B7

firmware/cyd_35r/flash.ps1

@@ -1,4 +1,4 @@
-# Flash archived CYD SGP30 firmware (no rebuild needed)
+# Flash archived CYD INMP441 sound-meter firmware for 3.5C (no rebuild needed)
 # Usage:
 #   .\flash.ps1
 #   .\flash.ps1 -Port COM5