feat: Multi-container site-packages support with isolated package directories

[sidnb13]

Summary

Adds support for multiple containers on the same remote host without package conflicts by using project-specific site-packages caching and dual path translation.

Changes

1. Project-Specific Site-Packages Mount

• Updated: docker-compose.yml.j2 template
• Before: All containers shared /usr/local/lib/pythonX.Y/dist-packages
• After: Each container uses ~/.cache/python-packages/${CONTAINER_NAME}
• Benefit: Complete isolation - different Python versions and packages per container

2. Dual Path Translation in LSP Proxy

• Updated: mlt/config.py - Added get_all_path_mappings()
• Updated: mlt/lsp_proxy.py - Translates both project and library paths
• Translates:
  • Project paths: /home/ubuntu/projects/X ↔ /workspace/X
  • Library paths: ~/.cache/python-packages/X ↔ /usr/local/lib/pythonX.Y/dist-packages

3. Documentation

• Updated: CLAUDE.md - Added "Multi-Container Support" section
• Documents how isolation works, examples, and benefits

Benefits

✅ Work on multiple branches simultaneously without conflicts
✅ Different Python versions per project
✅ Isolated dependencies per container
✅ Zed LSP works correctly for all containers
✅ Navigate to stdlib/library files in editor

Testing

• Verify multiple containers can run on same host
• Verify LSP works for each container independently
• Verify stdlib navigation works with project-specific packages
• Test with different Python versions

Breaking Changes

None - existing single-container setups continue to work. The site-packages mount path changes but this is transparent to users.