Feature request: configurable mouse cursor style (arrow vs I-beam)

[StrangeTeaCreature]

Description

Currently, Rio always displays an I-beam (text selection) mouse cursor over the terminal area. This differs from the behavior of traditional Windows terminals like PowerShell (conhost), which use a standard arrow cursor by default and only switch to I-beam when actively selecting text.

Expected behavior

Add a configuration option to control the mouse cursor style over the terminal area:

• Arrow (default system cursor) — switches to I-beam only when selecting text
• I-beam (current behavior) — always shows I-beam over terminal content

This is consistent with how PowerShell/conhost works on Windows: the cursor is a normal arrow pointer, and changes to I-beam only during text selection.

Current behavior

The mouse cursor is always displayed as I-beam over the terminal content area, making it look like you're always in "selection mode" even when just hovering.

Suggested config

# Mouse cursor style over terminal area
# Options: 'arrow', 'ibeam' (default: 'ibeam')
mouse-cursor = 'arrow'

Environment

• OS: Windows 11
• Rio version: latest
• Also affects other modern terminals (Alacritty, WezTerm) — but Rio has the opportunity to stand out by offering this option.