Add tech review automation

[riaankleinhans]

This PR adds a GitHub Actions workflow that automatically creates a tech review issue when the review/tech label is added to an issue.

What it does:

• Triggers when review/tech label is added to an issue
• Extracts project information from the source issue (supports multiple templates like gov-review.yml, joint-security-review.yaml, etc.)
• Checks for existing tech review issues for the same project (both open and closed)
• Creates a new tech review issue using the tech-review.yml template format if none exists
• Adds bidirectional links between the source issue and the created tech review issue
• Prevents duplicate comments and issues through idempotency checks

Features:

• Handles multiple issue template formats
• Exact project name matching to avoid false positives
• Error handling with user-friendly error messages
• Duplicate prevention (checks for existing comments/issues before creating)

Note: Only processes new label additions - does not process existing issues that already have the label.