Add MatchedGeometryEffect

[Dark-Existed]

Implement #922

[augmentcode]

🤖 Augment PR Summary

Summary: This PR adds a SwiftUI-compatible matchedGeometryEffect implementation to OpenSwiftUI, enabling views that share an id+namespace to interpolate geometry across insert/remove transitions.

Changes:

• Introduces View.matchedGeometryEffect and the underlying _MatchedGeometryEffect modifier with support for matching position/size/frame and optional clipping.
• Adds a matched-geometry scope (MatchedGeometryScope) that maintains per-id shared frame state and tracks source vs destination views.
• Implements shared-frame evaluation and animation state handling (SharedFrame/MatchedSharedFrame), including listener propagation and reset handling.
• Wires the feature into the view graph by creating a root matched-geometry scope when geometry is needed.
• Extends ViewTransform conversion APIs to support converting points between coordinate spaces (used by geometry matching).
• Adds an example view and a snapshot-based UI test demonstrating geometry matching during axis changes.

Technical Notes: The implementation relies on AttributeGraph rules to publish a shared frame in global space and converts it back into each view’s local space using ViewTransform during layout/display-list evaluation.

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[augmentcode]

MutableCollection where Element == CGPoint applies CGAffineTransform.inverted() / CGPoint.applying(_:) directly, while other affine paths in ViewTransform are guarded with #if canImport(CoreGraphics) and fall back to _openSwiftUIPlatformUnimplementedWarning().
On non-CoreGraphics platforms this can become a compile-time break (or silently change behavior compared to the existing guarded implementations).

Severity: medium

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