docs: add usage options for model short names and mcp command

[bherrmann7]

Addresses #2

Added documentation to README.md for two new usage patterns:

1. bb <model-short-name> - Uses model configuration from ~/.bb/models.json
2. bb mcp - Displays configured MCP servers and exits

Generated with Claude Code

[claude]

Pull Request Review

Overall, this is a well-focused documentation PR that accurately describes the implemented features. The changes are clear and helpful for end users. ✅

Code Quality & Best Practices

Strengths:

• ✅ Documentation accurately reflects the actual implementation in Program.cs:54-58 (mcp command) and Program.cs:72-93 (model short names)
• ✅ Clear, concise examples that follow the existing README structure
• ✅ Proper use of code blocks with bash syntax highlighting
• ✅ Appropriate cross-references to configuration files (~/.bb/models.json and ~/.bb/mcp.json)

Minor Issues:

• Line 23: Trailing whitespace removed (good cleanup)
• The documentation could benefit from mentioning the bb models command (implemented in Program.cs:46-51) as it complements the model short name feature

Potential Bugs or Issues

None identified - The documented features are correctly implemented:

• bb mcp command verified in Program.cs:54-58 → calls McpConfigLoader.DisplayMcpServers() → verified in McpConfigLoader.cs:19-65
• bb <model-short-name> verified in Program.cs:72-93 → uses ModelManager.GetModelByShortName() → verified in ModelManager.cs:19-22

Performance Considerations

N/A - This is a documentation-only PR with no performance implications.

Security Concerns

None - The documentation appropriately references secure configuration files in the user's home directory. The implementation properly obfuscates API keys in output (Program.cs:147-149).

Test Coverage

Observation:

• Existing test file test_auto_add_model.cs covers the ModelManager.AddModelIfNotExists() functionality
• The bb mcp command (display-only) and model short name lookup are not explicitly tested
• Recommendation: Consider adding integration tests for these CLI command paths in the future, though it's not required for this documentation PR

Suggestions for Enhancement

1. Add the bb models command to the documentation:

   bb models

   Shows all configured models from ~/.bb/models.json (implemented in Program.cs:46-51)

2. Consider adding an example showing what the output looks like for both commands to set user expectations

3. Minor typo in issue Docs #2: The issue description says "uses the short name to set the model" which could be clearer - the documentation correctly specifies it sets "model, endpoint, and key"

Summary

This PR successfully addresses issue #2 and provides valuable user-facing documentation. The implementation is sound and the documentation is accurate.

Recommendation: ✅ APPROVE

The only suggestion would be to optionally mention the bb models command as well, since it's related and useful for discovering available short names.