Fix/antv wechat svg paints

[M4TRIX04]

Summary

Fix AntV Infographic SVG graphics appearing with incorrect or black fills when copied from the Markdown editor into the WeChat Official Account editor.

Some AntV graphics use embedded SVG paint resources that are not preserved correctly during clipboard export. This change resolves those paint references and removes transparent overlays where necessary, improving compatibility with WeChat's SVG rendering.

Changes

• Resolve embedded SVG paint references during WeChat clipboard sanitization.
• Preserve the intended colors of AntV Infographic graphics.
• Handle transparent overlays that may interfere with the exported result.
• Add regression tests for the affected SVG structures.

Related Issues

No existing issue linked yet.

Test Procedure

• Changes cherry-picked cleanly onto the latest upstream main.
• git diff --check
• Automated unit tests (pending CI)
• Lint (pending CI)
• Original implementation verified by copying affected AntV Infographic graphics into the WeChat Official Account editor.

Notes

This PR is intentionally limited to AntV SVG clipboard compatibility. It does not include Docker configuration or unrelated Mermaid changes.

[github-actions]

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