feat: Add keyboard shortcut to toggle help screen popup

[brainJamStark]

Description

The help screen is currently displayed when the application launches, but when large tables are displayed, the help information scrolls off the page and becomes inaccessible. Users need a way to bring up the help screen on demand.

Problem

• Help screen is only shown at application startup
• Large table outputs push help information off-screen
• No way to redisplay help without restarting the application
• Users may need to reference keyboard shortcuts while working

Proposed Solution

Add a keyboard shortcut to toggle a help screen popup:

• Ctrl-H (Linux/Windows)
• Cmd-H (macOS) or Ctrl-H for consistency

The help popup should:

• Display over current content (modal or overlay)
• Show all keyboard shortcuts and commands
• Be dismissible with ESC or the same toggle key
• Not interfere with current application state

User Benefits

• Quick access to help information at any time
• Better user experience when learning the application
• No need to restart to see keyboard shortcuts
• Improved discoverability of features

Implementation Considerations

• Design popup/modal UI
• Implement keyboard shortcut handler
• Ensure help content is up-to-date
• Handle cross-platform keyboard shortcuts (Ctrl vs Cmd)
• Add help toggle to existing help text

[joaquincasares]

F2 takes you back to the "main page" which shows the help text and scrolling up and using alt+up works.

But to Brian's point, ctrl-H would be nicer.