layout: add weighted child sizing

[GGRei]

Summary

Add gui.weighted() for assigning proportional main-axis space to container children.

A row distributes width, while a column or circle distributes height:

gui.weighted(weight: 2, view: gui.button(...))

The implementation:

• supports constrained 1:1:2-style layouts;
• redistributes space correctly around minimum and maximum sizes;
• recalculates proportions when the parent is resized;
• preserves the existing layout path when no weights are used;
• adds no extra Layout node and does not change the View interface;
• rejects invalid weights and unsupported configurations explicitly;
• includes documentation and a resizable button example.

Validation

• Weighted layout tests pass with Clang in normal and production modes.
• Existing layout, wrap, border, GC leak and GC lint tests pass.
• Documentation and formatting checks pass.
• Shape remains 200 bytes.
• No allocations occur during distribution after warm-up.
• examples/weighted_layout.v compiles cleanly with -W and runs successfully.

[chatgpt-codex-connector]

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Reviewed commit: 06ccbd96d7

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[GGRei]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Already looking forward to the next diff.

Reviewed commit: 06ccbd96d7

ℹ️ About Codex in GitHub

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• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

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