Write test cases for packaging and publishing steps (TDD)

[shankarpandala]

According to our TDD plan for the VS Code extension, we need to write tests for packaging (vsce package) and publishing (vsce publish) before implementing. These tests should validate that:

• The extension .vsix is generated successfully with the correct metadata.
• The package.json fields (name, version, publisher, engines) are properly validated.
• Error handling occurs when mandatory fields are missing or invalid.
• CI scripts or commands (vsce publish) run as expected.

Follow TDD: write failing tests in Jest for these scenarios, then implement any necessary scripts or CI configuration to satisfy them.