fix: keybinding support

[gannonh]

Add keybinding support for Pinit extension

This PR adds keyboard shortcut support to the Pinit extension, allowing users to pin files and folders with a keystroke.

Key Changes:

• Implemented robust file path detection that works with keyboard shortcuts
• Added error handling and user feedback when path detection fails
• Updated command implementation to work seamlessly from both context menu and keyboard
• Added default keybinding (Ctrl+P Ctrl+I for Windows/Linux, Shift+Cmd+I for Mac)
• Fixed TypeScript errors related to error handling
• Added build script for easier development

Details:

The main issue was that the original implementation only worked when triggered from the context menu, as it expected a file to be directly passed to the command. This implementation adds multiple fallback mechanisms to detect the current file:

1. First checks if triggered from context menu
2. Then checks if there's an active text editor
3. Then uses explorer selection API
4. As a last resort, tries to use the clipboard

This makes the extension much more flexible and user-friendly by enabling keyboard-driven workflows.