Add sample video generator, website CLI/local server, and HLS publish fallback with tests

[Bowenislandsong]

Motivation

• Provide a small synthetic MP4 generator and scripts for publishing and locally serving website preview content for prototype validation.
• Improve website publisher resilience by preferring HLS playlists but falling back to MP4 or copying the original when conversion isn't available.
• Expose CLI utilities and ensure tests exercise video tooling and publisher fallback behavior.

Description

• Added a tiny synthetic video tool at src/studio/tools/generate_sample_video.py and a script scripts/publish_sample_movie.py that generates a sample clip and publishes it via the website publisher API.
• Added a local static server script scripts/run_website_local.py to serve the generated website/public directory for previews.
• Added src/studio/website/cli.py providing publish and list subcommands for interacting with the MoviePublisher from the command line.
• Updated src/studio/website/publisher.py to prefer hls/stream.m3u8, then hls/stream.mp4, and finally copy the direct source video if neither HLS output is present.
• Added top-level package marker src/__init__.py and updated pyproject.toml to include . in pytest pythonpath for tests.
• Added automated tests: tests/test_sample_video_tool.py, tests/test_website_publisher.py, and tests/test_media_video.py to cover generation and publisher fallback logic.

Testing

• Ran the test suite with pytest -q targeting the added tests tests/test_sample_video_tool.py, tests/test_website_publisher.py, and tests/test_media_video.py.
• All added tests passed successfully.

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Codex Task