Add VS Code Marketplace publishing infrastructure

[Copilot]

Configure the extension for publication to the VS Code Marketplace with automated CI/CD.

Changes

• Package metadata: Added publisher, repository, bugs, homepage, keywords, and license fields to package.json
• Publishing tooling: Added @vscode/vsce with package and publish scripts
• Image format compliance: Converted SVG images to PNG (Marketplace requirement) and updated README references
• Package exclusions: Created .vscodeignore to exclude development files from published package (~145 KB, 18 files)
• Automated publishing: Added .github/workflows/publish.yml that builds, tests, and publishes on version tags
• Documentation: Added PUBLISHING.md explaining bundling approach, manual/automated publishing methods, and PAT setup

Publishing

The extension uses esbuild to bundle all dependencies into dist/extension.js, enabling the --no-dependencies flag for optimal package size and startup performance.

To publish:

pnpm version patch  # or minor/major
git push --follow-tags  # triggers GitHub Actions workflow

Requires VS_MARKETPLACE_TOKEN GitHub secret with Azure DevOps PAT (Marketplace > Manage permissions).

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https /usr/lib/apt/methods/https (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Publish on VS Code Marketplace</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Publish on VS Code Marketplace #19

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