feat: release 0.2.0 with official validator wheel and release CI

[fabricebrito]

Upgrade the extension to 0.2.0 with the official eoap-validator 0.2.0 PyPI wheel. Add a retrieval task that verifies the pinned checksum and refreshes attribution, and key managed environments by artifact checksum so existing installations pick up the new bundle.

Upgrade @vscode/vsce to 4.0.0 to remove the vulnerable packaging dependency chain. CI now audits dependencies and attaches the packaged VSIX to published GitHub releases. Builds require Node.js 22 or newer, matching CI.

Validation:

• Compilation and linting passed; all 23 tests passed.
• npm audit reports zero vulnerabilities.
• task retrieve-validator verified the published wheel checksum and attribution.
• npm run package generated eoap-validator-vscode-0.2.0.vsix.
• Release workflow configuration was validated locally; the upload will be exercised on a published release.