Implement Basic Test Framework

[codevalve]

Set up a testing framework and add initial tests for core functionality.

Tasks:

• Choose and set up testing framework
• Create test directory structure
• Add unit tests for core functions
• Add integration tests for session start script
• Update package.json test script
• Add test documentation
• Set up test GitHub Action

Current Status:

• package.json has a placeholder test script that exits with error
• No tests directory exists
• No test framework chosen

This will help ensure reliability and make it easier to accept contributions.

[codevalve]

Completed in PR #15. Implemented comprehensive test framework with:

• Jest for JavaScript unit testing
• BATS for shell script testing
• GitHub Actions workflow for CI
• Test documentation in README