fix: add --no-sandbox to antigravity launch command

Electron apps crash in Docker without --no-sandbox and
--disable-dev-shm-usage, same as Chrome. VSCode handles this
internally; Antigravity does not.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

chart/Chart.yaml

@@ -2,5 +2,5 @@ apiVersion: v2
 name: devcontainer
 description: Antigravity Dev Container with Happy Coder AI assistant
 type: application
-version: 0.1.7
+version: 0.1.8
 appVersion: "latest"

scripts/startapp.sh

@@ -21,7 +21,8 @@ echo "Workspace: $WORKSPACE_DIR"
 case "$IDE" in
     antigravity)
         echo "Opening Google Antigravity in: $WORKSPACE_DIR"
-        exec antigravity --new-window --wait "$WORKSPACE_DIR"
+        # --no-sandbox and --disable-dev-shm-usage are required for Electron apps in Docker
+        exec antigravity --no-sandbox --disable-dev-shm-usage --new-window --wait "$WORKSPACE_DIR"
         ;;
     none)
         echo "IDE=none: no IDE launched, keeping container alive."