App layout uses CSS Grid with Top-Left video placeholder (Film icon), Top-Right empty container for Phase 1.2 input, and Bottom full-width container for Phase 1.2 response. Includes Layout test verifying Phase 2 placeholder text and API client tests verifying baseURL and mocked endpoint calls.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Woody