fix: use compiler.cpp.extra_flags to avoid clobbering platform defines

build.extra_flags replaces the esp32 core's platform-level flags,
which include CONFIG_IDF_TARGET_ESP32S3 — required by Arduino_GFX
for RGB panel support. compiler.cpp.extra_flags appends safely.

sketches/doorbell-touch-esp32-32e/mise.toml

@@ -1,15 +1,10 @@
+
 [tools]
 arduino-cli = "latest"
 lazygit = "latest"
 python = "latest"
 ruby = "latest"
 
-# ═══════════════════════════════════════════════════════════════════
-# Default target — override with: BOARD_TARGET=waveshare_s3 mise run compile
-# ═══════════════════════════════════════════════════════════════════
-[env]
-BOARD_TARGET = "e32r35t"
-
 [tasks.install-core]
 run = "arduino-cli core update-index && arduino-cli core install esp32:esp32"
 
@@ -62,7 +57,7 @@ echo "║ FQBN:     $FQBN"
 echo "║ Flags:    $BUILD_FLAGS"
 echo "╚══════════════════════════════════════════════════╝"
 arduino-cli compile --fqbn "$FQBN" \
-  --build-property "build.extra_flags=$BUILD_FLAGS" .
+  --build-property "compiler.cpp.extra_flags=$BUILD_FLAGS" .
 """
 
 [tasks.upload]
@@ -105,9 +100,9 @@ case "${BOARD_TARGET:-e32r35t}" in
 esac
 PORT=$(arduino-cli board list | grep -iE "$PORT_PATTERN" | head -1 | awk '{print $1}')
 if [ -z "$PORT" ]; then
-  echo "No matching port for pattern: $PORT_PATTERN"
-  arduino-cli board list
-  exit 1
+echo "No matching port for pattern: $PORT_PATTERN"
+arduino-cli board list
+exit 1
 fi
 arduino-cli monitor -p "$PORT" -c baudrate=115200
 """