Add VulnHawk - AI-powered code security scanner

[momenbasel]

Summary

• Adds VulnHawk to the Other Useful Repositories section
• VulnHawk is an open-source (MIT license) AI-powered static code security scanner written in Python
• It uses AI to detect business logic vulnerabilities that traditional SAST tools (Semgrep, CodeQL) miss: missing authorization checks, IDOR, logic flaws
• Supports Python, JavaScript, TypeScript, and Go
• Provides CLI, GitHub Action integration, SARIF output, and multiple LLM backends

Placed alphabetically after Vulhub per contribution guidelines.

[Copilot]

Pull request overview

Adds a new security tool repository link (VulnHawk) to the “Other Useful Repositories” section of the README to expand the curated resource list.

Changes:

• Add VulnHawk repository entry with a description of its SAST/LLM-focused capabilities.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[momenbasel]

Rebased onto current master - the conflict came from the table-spacing normalisation in #206. Now a single commit adding one row in the normalised format, and mergeable again.