Add folder anatomy (scripts/agent.py + references/api-reference.md) for 648 cybersecurity skills

Complete skill folder anatomy across all cybersecurity skills:
- scripts/agent.py: 80-150 line Python agents using real libraries (impacket,
  boto3, azure-mgmt-*, kubernetes, pefile, yara, scapy, shodan, stix2, etc.)
- references/api-reference.md: real API documentation with method signatures
- LICENSE: MIT license for all skill folders

skills/performing-web-application-scanning-with-nikto/references/api-reference.md

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+# API Reference: Web Application Scanning with Nikto
+
+## Nikto CLI Options
+
+| Flag | Description |
+|------|-------------|
+| `-h <host>` | Target hostname or IP |
+| `-port <ports>` | Target ports (comma-separated) |
+| `-ssl` | Force SSL/TLS connection |
+| `-Format xml\|json\|csv\|htm` | Output format |
+| `-output <file>` | Save results to file |
+| `-Tuning <options>` | Scan tuning categories |
+| `-Plugins <list>` | Specific plugins to run |
+| `-maxtime <seconds>s` | Maximum scan duration |
+| `-nointeractive` | Disable interactive prompts |
+| `-useproxy <url>` | Use HTTP proxy |
+| `-id <user:pass>` | HTTP Basic auth credentials |
+
+## Tuning Categories
+
+| Code | Category |
+|------|----------|
+| 1 | Interesting File / Seen in logs |
+| 2 | Misconfiguration / Default File |
+| 3 | Information Disclosure |
+| 4 | Injection (XSS/Script/HTML) |
+| 5 | Remote File Retrieval - Inside Web Root |
+| 6 | Denial of Service |
+| 7 | Remote File Retrieval - Server Wide |
+| 8 | Command Execution / Remote Shell |
+| 9 | SQL Injection |
+| 0 | File Upload |
+
+## XML Output Structure
+
+| Element | Description |
+|---------|-------------|
+| `<niktoscan>` | Root element |
+| `<scandetails>` | Scan metadata |
+| `<item>` | Individual finding |
+| `<item id="..." osvdbid="...">` | Finding with OSVDB reference |
+| `<uri>` | Affected URI path |
+| `<description>` | Finding description |
+
+## Python Libraries
+
+| Library | Version | Purpose |
+|---------|---------|---------|
+| `subprocess` | stdlib | Execute Nikto CLI |
+| `xml.etree.ElementTree` | stdlib | Parse Nikto XML output |
+| `json` | stdlib | Report generation |
+
+## References
+
+- Nikto GitHub: https://github.com/sullo/nikto
+- Nikto Documentation: https://cirt.net/Nikto2
+- OSVDB (archived): https://vulndb.cyberriskanalytics.com/