Experimental: OpenTUI alpha frontend

[man612]

Status

Experimental UI preview only. Do not merge yet and do not recommend this frontend for normal use.

The stable/recommended interface remains the PowerShell TUI launched through FixPrinter.bat on main.

What this explores

• OpenTUI + Solid frontend with mouse and keyboard interaction
• responsive terminal layout for non-fullscreen windows
• command palette, dialogs, loading feedback, and an in-app guide
• English / Indonesian UI localization through a dedicated i18n layer
• reuse of the existing PowerShell diagnosis/repair engine through EngineApi.ps1
• standalone Windows executable build path for development previews

Current limitations

• UI/UX still needs substantial redesign and hands-on testing
• not a replacement for the stable PowerShell TUI
• no stable binary release is being published from this branch
• real-world repair interaction coverage is incomplete

Validation completed

• existing v4 static validation passes
• existing diagnosis runtime smoke passes without state changes
• PowerShell source/API parse successfully
• OpenTUI TypeScript typecheck passes
• alpha packaging build succeeds

This PR should stay in Draft until the modern frontend is clearly better than the stable interface in usability and reliability.