This fixes issue #3922 where `llama stack list` only showed distributions
after they were run. Now the command shows both:
- Built-in distributions from the source code (e.g., starter, nvidia, dell)
- Built distributions from ~/.llama/distributions
Changes:
- Updated _get_distribution_dirs() to discover built-in distributions
- Added a "Source" column to distinguish "built-in" vs "built" distributions
- Built distributions override built-in ones with the same name
- Added comprehensive unit tests to verify the fix
Closes#3922🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
