dxt to uvx mcpb

[drernie]

Instead of copying the source code, just have the mcpb (was DXT) uvx run the quilt_mcp package.

1. Rename extension (and targets, etc.)
2. add console script
3. Remove complex copying

[drernie]

Claude Desktop Extensions now use the .mcpb (MCP Bundle) file extension instead of .dxt. Existing .dxt extensions will continue to work, but we recommend developers use .mcpb for new extensions going forward. All functionality remains the same - this is purely a naming convention update.
https://www.anthropic.com/engineering/desktop-extensions