Complete folder anatomy for all 649 cybersecurity skills + update LICENSE to Mahipal

- Add scripts/agent.py and references/api-reference.md to all remaining skills
- Update all 648 LICENSE files: copyright now reads 'Mahipal'
- Add implementing-security-monitoring-with-datadog (new skill with full anatomy)
- All 649 skills now have: SKILL.md, LICENSE, scripts/agent.py, references/api-reference.md

skills/testing-for-host-header-injection/references/api-reference.md

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+# API Reference: Testing for Host Header Injection
+
+## Alternative Host Headers
+
+| Header | Description |
+|--------|-------------|
+| `X-Forwarded-Host` | Proxy-set original host |
+| `X-Host` | Alternative host header |
+| `X-Forwarded-Server` | Forwarded server name |
+| `X-HTTP-Host-Override` | Host override |
+| `Forwarded: host=` | RFC 7239 forwarded header |
+| `X-Original-URL` | URL rewrite override |
+
+## Attack Scenarios
+
+| Attack | Severity | Impact |
+|--------|----------|--------|
+| Password reset poisoning | Critical | Token theft via poisoned link |
+| Web cache poisoning | Critical | Stored XSS via cached response |
+| SSRF via Host | High | Internal service access |
+| Virtual host bypass | Medium | Access to other vhosts |
+| Open redirect | Medium | Phishing via redirect |
+
+## Test Techniques
+
+| Technique | Payload Example |
+|-----------|----------------|
+| Direct Host override | `Host: evil.com` |
+| Alternative header | `X-Forwarded-Host: evil.com` |
+| Port injection | `Host: target.com:@evil.com` |
+| Double Host | Two Host headers |
+| Absolute URL | `GET http://target.com/ Host: evil.com` |
+
+## Python Libraries
+
+| Library | Version | Purpose |
+|---------|---------|---------|
+| `requests` | >=2.28 | HTTP requests with custom headers |
+| `json` | stdlib | Report generation |
+
+## References
+
+- PortSwigger Host Header: https://portswigger.net/web-security/host-header
+- OWASP Host Header: https://owasp.org/www-project-web-security-testing-guide/