Script Kit UI Testing

All UI testing uses the stdin JSON protocol. Never pass scripts as CLI arguments.

Stdin JSON Protocol

Correct:

echo '{"type":"run","path":"'"$(pwd)"'/tests/smoke/test-editor-height.ts"}' | \
  SCRIPT_KIT_AI_LOG=1 ./target/debug/script-kit-gpui 2>&1

Wrong (does nothing):

./target/debug/script-kit-gpui tests/smoke/hello-world.ts

Always set SCRIPT_KIT_AI_LOG=1 when testing (saves ~70% tokens).