Add bundled Ghostty helper regression test

.github/workflows/ci.yml

@@ -154,6 +154,12 @@ jobs:
             fi
           fi
 
+      - name: Run bundled Ghostty theme picker helper regression
+        run: |
+          set -euo pipefail
+          CMUX_SOURCE_PACKAGES_DIR="$PWD/.ci-source-packages" \
+            ./tests/test_bundled_ghostty_theme_picker_helper.sh
+
       - name: Run CLI version memory guard regression
         run: |
           set -euo pipefail

tests/test_bundled_ghostty_theme_picker_helper.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SOURCE_PACKAGES_DIR="${CMUX_SOURCE_PACKAGES_DIR:-$PWD/.ci-source-packages}"
+DERIVED_DATA_PATH="${CMUX_DERIVED_DATA_PATH:-$PWD/.ci-bundled-ghostty-helper}"
+CONFIGURATION="${CMUX_CONFIGURATION:-Debug}"
+
+case "$CONFIGURATION" in
+  Debug)
+    APP_NAME="cmux DEV.app"
+    ;;
+  Release)
+    APP_NAME="cmux.app"
+    ;;
+  *)
+    echo "FAIL: unsupported configuration $CONFIGURATION" >&2
+    exit 1
+    ;;
+esac
+
+mkdir -p "$SOURCE_PACKAGES_DIR"
+rm -rf "$DERIVED_DATA_PATH"
+
+xcodebuild \
+  -project GhosttyTabs.xcodeproj \
+  -scheme cmux \
+  -configuration "$CONFIGURATION" \
+  -clonedSourcePackagesDirPath "$SOURCE_PACKAGES_DIR" \
+  -disableAutomaticPackageResolution \
+  -derivedDataPath "$DERIVED_DATA_PATH" \
+  -destination "platform=macOS" \
+  build
+
+APP_PATH="$DERIVED_DATA_PATH/Build/Products/$CONFIGURATION/$APP_NAME"
+HELPER_PATH="$APP_PATH/Contents/Resources/bin/ghostty"
+
+if [ ! -x "$HELPER_PATH" ]; then
+  echo "FAIL: bundled Ghostty theme picker helper missing at $HELPER_PATH" >&2
+  exit 1
+fi
+
+echo "PASS: bundled Ghostty theme picker helper present at $HELPER_PATH"