fix : LayoutDebug grid renders Unicode box-drawing chars without ASCII fallback

[tmdeveloper007]

Summary of What Needs to be Done

The LayoutDebug widget (packages/widgets/src/display/LayoutDebug.ts) renders its grid overlay using hardcoded Unicode box-drawing characters (│ and ─) instead of checking caps.unicode. In terminals without Unicode support, the grid renders as garbage characters.

Changes that Need to be Made

1. In packages/widgets/src/display/LayoutDebug.ts, update _renderGrid() to use caps.unicode ? '│' : '|' for vertical grid lines and caps.unicode ? '─' : '-' for horizontal grid lines.
2. Add tests verifying that the ASCII fallback grid renders correctly when caps.unicode is false.

Impact that it would Provide

The LayoutDebug grid overlay will be readable in any terminal environment, making debugging layouts more reliable across different terminal configurations.

Note: Please assign this issue to the tmdeveloper007 account.

[github-actions]

✅ Auto-assigned to @tmdeveloper007 (issue opener).

Open your PR by 2026-08-10 (7 days). The bot frees this issue for another contributor after that date.

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