Migrates package structure to src/ layout following Python packaging
best practices.
All code moved from `llama_stack/` to `src/llama_stack/`. Public API
unchanged - imports remain `import llama_stack.*`.
Updated build configs, pre-commit hooks, scripts, and GitHub workflows
accordingly. All hooks pass, package builds cleanly.
**Developer note**: Reinstall after pulling: `pip install -e .`
## Summary:
This commit adds infinite scroll pagination to the chat completions and
responses tables.
## Test Plan:
1. Run unit tests: npm run test
2. Manual testing: Navigate to chat
completions/responses pages
3. Verify infinite scroll triggers when approaching
bottom
4. Added playwright tests: npm run test:e2e