feat: show tray menu only on right click

[SeanTong11]

Summary

This updates the tray icon interaction so left click toggles the main window visibility, while the tray context menu is reserved for
right click.

Background

Discussed in #405.

The proposed behavior matches the more common Windows tray pattern:

• Left click: show/hide the main window
• Right click: open the tray menu

Changes

• Adds .show_menu_on_left_click(false) to the tray icon builder.
• Keeps the existing left-click window visibility toggle.
• Keeps the tray menu available through right click.

Testing

Tested manually on Windows:

• Left-clicking the tray icon restores the main window.
• Left-clicking the tray icon again hides the main window.
• Left-clicking the tray icon does not open the tray menu.
• Right-clicking the tray icon opens the tray menu.

Platform notes

As noted in #405:

• macOS may ignore show_menu_on_left_click(false) because tray/menu-bar click behavior is often controlled by the OS.
• Linux AppIndicator behavior may vary by desktop environment and may not consistently distinguish left/right click.

[Splode]

Looks good! On macOS, left-click now toggles the window application, and right-click shows the menu, which I think is an acceptable behavior. Linux retains the original behavior where left and right click both show the menu.

Thanks again for another contribution!