Feature/replace outline

[NailxSharipov]

Summary

It refactors buffering to follow the original boolean flow instead of a custom path, which makes behavior more consistent and easier to trust.
It also adds more careful handling of edge and degenerate inputs, so results are more predictable in tricky cases.

Changes

Testing

• cargo test
• cargo fmt
• cargo clippy

Checklist

• Added tests for new behavior or bug fixes
• Updated docs/examples if needed

[codecov]

Codecov Report

❌ Patch coverage is 81.72757% with 55 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
iOverlay/src/float/overlay.rs	0.00%	10 Missing ⚠️
iOverlay/src/mesh/stroke/offset.rs	76.19%	10 Missing ⚠️
iOverlay/src/mesh/outline/builder.rs	88.88%	7 Missing ⚠️
iOverlay/src/mesh/outline/offset.rs	89.55%	7 Missing ⚠️
iOverlay/src/core/overlay.rs	69.23%	4 Missing ⚠️
iOverlay/src/mesh/outline/builder_join.rs	83.33%	4 Missing ⚠️
iOverlay/src/mesh/stroke/builder_join.rs	55.55%	4 Missing ⚠️
iOverlay/src/mesh/outline/section.rs	75.00%	3 Missing ⚠️
iOverlay/src/mesh/outline/uniq_iter.rs	92.50%	3 Missing ⚠️
iOverlay/src/mesh/subject.rs	33.33%	2 Missing ⚠️
... and 1 more

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