chore(vscode): add icon, clean dist artifacts

[fi3ework]

Summary

• add icon
• clean vsix dist tar
• fix hoist deps to make vsce happy

Related Links

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

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[Copilot]

Pull Request Overview

This PR enhances the VSCode extension configuration by adding an icon, cleaning up distribution artifacts, and resolving dependency hoisting issues for the vsce packaging tool.

Key changes:

• Added icon support with automatic download fallback
• Updated workspace configuration to hoist @secretlint dependencies for vsce compatibility
• Improved documentation table formatting and added new configuration option

Reviewed Changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

File	Description
pnpm-workspace.yaml	Added hoistPattern for @secretlint dependencies to satisfy vsce requirements
packages/vscode/package.json	Added icon field and preinstall script to download icon if missing
packages/vscode/README.md	Reformatted configuration table and added logLevel setting documentation
packages/vscode/.vscodeignore	Added new file to specify which files to include in the extension package

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[Copilot]

The preinstall script uses shell syntax that may not work on Windows. Consider using a cross-platform solution like downloading the icon through a Node.js script or including the icon file directly in the repository.

Suggested change

	"preinstall": "[ -f icon.png ] || curl https://assets.rspack.rs/rstest/rspress-logo-512x512.png --output icon.png",
	"preinstall": "node ./scripts/download-icon.js",