终端命令提示框，及vim光标 背景色太深遮挡终端内容 #5

Description

建议提示框及光标透明度调低以显示遮挡内容

如图，无法显示选中的选项

Environment

• GPUI: [e.g., v0.2.2]
• GPUI Component: [e.g., v0.4.0]
• Platform: [e.g., macOS 26, Windows 11, Ubuntu 20.04]

Steps to Reproduce

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Screenshots

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Expected

A clear and concise description of what you expected to happen.

Actual

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