Add Ratio node type for media feature ratio values, fix clone() nesting

[bartveneman]

Media features like aspect-ratio: 16/9 were exposing .value as just the numerator, silently dropping the denominator. Add a dedicated RATIO node type with left/right accessors so ratio values are represented as one coherent node, matching how scalar features (min-width: 768px) already work. Plain numbers (aspect-ratio: 1) are unaffected and still parse as a bare Number.

Also fix CSSNode.clone(), which assigned nested CSSNode properties (value, left, right, selector) directly instead of recursively cloning them — plain-object output leaked live arena-backed node instances instead of serializable data.

[github-actions]

⚠️ Duplicate Dependencies (found: 3, threshold: 2)

📦 Package	📋 Versions
@emnapi/core	3 versions root@ @vitest/coverage-v8@4.1.10 ... rolldown@1.1.5 @rolldown/binding-wasm32-wasi@1.1.5 @emnapi/core@1.11.1 root@ knip@6.29.0 oxc-parser@0.140.0 @oxc-parser/binding-wasm32-wasi@0.140.0 @emnapi/core@1.11.2 root@ tsdown@0.22.14 rolldown@1.2.1 @rolldown/binding-wasm32-wasi@1.2.1 @emnapi/core@2.0.0-alpha.3
@emnapi/runtime	3 versions root@ @vitest/coverage-v8@4.1.10 ... rolldown@1.1.5 @rolldown/binding-wasm32-wasi@1.1.5 @emnapi/runtime@1.11.1 root@ knip@6.29.0 oxc-parser@0.140.0 @oxc-parser/binding-wasm32-wasi@0.140.0 @emnapi/runtime@1.11.2 root@ tsdown@0.22.14 rolldown@1.2.1 @rolldown/binding-wasm32-wasi@1.2.1 @emnapi/runtime@2.0.0-alpha.3
@oxc-project/types	3 versions root@ @vitest/coverage-v8@4.1.10 ... vite@8.1.5 rolldown@1.1.5 @oxc-project/types@0.139.0 root@ knip@6.29.0 oxc-parser@0.140.0 @oxc-project/types@0.140.0 root@ tsdown@0.22.14 rolldown@1.2.1 @oxc-project/types@0.142.0

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⚠️ Package Size Increase

📦 Package	📏 Base Size	📏 Source Size	📈 Size Change
@projectwallace/css-parser	40.6 kB	41.1 kB	+562 B