Platform-specific key-hint formatting for TUI

What feature would you like to see?

Add platform-specific key-hint formatting in the TUI for clearer, more consistent shortcut display.

Proposal

• Keep all keybindings and Windows/Linux behavior unchanged.
• On macOS:

• Include Fn+Arrow alternatives for compact keyboards (MacBook, Magic Keyboard):

• Page Up (Fn+↑)
• Page Down (Fn+↓)
• Home (Fn+←)
• End (Fn+→)

• Update modifier labels and symbols to follow macOS conventions (e.g., ⌃, ⌥, ⇧).

• If the standard symbols are displayed, the full key names (like “Control” or “Option”) can optionally be omitted for a cleaner, Apple-style appearance.

Implementation route I took

• Add cfg(target_os = "macos") handling in the key-hint utility.
• Map macOS modifiers to Apple symbols (⌃, ⌥, ⇧).
• Append Fn+Arrow notes for Page Up, Page Down, Home, and End on macOS.
• Keep Windows and Linux rendering unchanged.
• Verify output and update snapshots to confirm platform consistency.

Goal
Match native platform conventions and improve clarity for macOS users, especially those on compact keyboards.

Additional information

_No response_