Remove sudo from startup scripts

baseimage-gui already runs startapp.sh as the app user (UID 1000),
so sudo -u is unnecessary and fails since 'app' is not in sudoers.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

scripts/startapp.sh

@@ -18,5 +18,4 @@ echo "Opening Antigravity in: $WORKSPACE_DIR"
 
 # Start Antigravity (VSCode) in the workspace directory as claude user
 # The baseimage-gui will handle the GUI display
-RUN_UID="${USER_ID:-1000}"
-exec sudo -u "#$RUN_UID" code --new-window --wait "$WORKSPACE_DIR"
+exec code --new-window --wait "$WORKSPACE_DIR"