chore: onboard stepsecurity and apply security best practice

[ali-kafel]

This pull request updates the GitHub Actions CI workflow to improve security and maintainability. The main changes are the addition of a hardened runner step, updated permissions, and pinning the actions/checkout action to a specific commit.

Security enhancements:

• Added the step-security/harden-runner action to block unauthorized network egress and enforce a global allowed endpoints policy, increasing the security of the CI runner.
• Granted id-token: write permissions to the workflow, which is required for some secure workflows and integrations.

Dependency management:

• Pinned actions/checkout to a specific commit hash (v3.6.0) for improved supply chain security and reproducibility.