Implement the Probot App, Notification workflow

[RajivBB]

Summary

Update and enhance the GitHub workflows to improve CI/CD automation and PR/issue management. This includes notifications, stale PR handling, pre-commit checks, and mergeable configuration.

Scope of Work

1. Notification Workflow

• Update the existing notification workflow to trigger on merges to develop and main branches.
• Add events for:
  • New GitHub issues
  • Updated GitHub issues
  • PR opened
  • PR comments or conversation activity
  • PR closure or merge

2. Mergeable Configuration

• Add or update .github/mergeable.yml to improve PR mergeability checks.

3. Stale Workflow

• Automate marking inactive PRs/issues as stale and closing them after a defined period.

4. Pre-Commit Workflow

• Add or update pre-commit workflow to run checks across all files for Python, Go, Terraform, and frontend code.
• Ensure default pre-commit configuration is applied if a repository config is missing.

Expected Outcome

• Automated notifications for key GitHub events.
• Consistent pre-commit checks before merges.
• Stale PR/issue cleanup is automated.
• Mergeable workflow ensures only ready-to-merge PRs can be merged.