update testcases and add GH pipeline for it

[naman-contentstack]

version bump:
1.6.0 -> 1.6.1

[Copilot]

Pull Request Overview

This PR updates the version from 1.6.0 to 1.6.1 and enhances test setup by standardizing authentication mocking across app command tests and enabling the GitHub Actions unit test workflow.

• Updated package version from 1.6.0 to 1.6.1 with corresponding documentation updates
• Standardized authentication stubbing across all app command test files for consistent test isolation
• Enabled GitHub Actions workflow for automated unit testing on pull requests

Reviewed Changes

Copilot reviewed 11 out of 12 changed files in this pull request and generated 2 comments.

File	Description
package.json	Version bump from 1.6.0 to 1.6.1
README.md	Updated version references and GitHub links from 1.5.0/1.6.0 to 1.6.0
test/unit/commands/app/*.test.ts	Added consistent authentication mocking setup across all app command tests
.github/workflows/unit-test.yml	Enabled GitHub Actions workflow for unit testing