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/implementing-api-schema-validation-security/references/api-reference.md

@@ -0,0 +1,61 @@
+# API Reference: Implementing API Schema Validation Security
+
+## jsonschema (Python)
+
+```python
+import jsonschema
+schema = {
+    "type": "object",
+    "properties": {
+        "name": {"type": "string", "maxLength": 100},
+        "email": {"type": "string", "format": "email"},
+    },
+    "required": ["name", "email"],
+    "additionalProperties": False,  # Prevent mass assignment
+}
+jsonschema.validate(instance=payload, schema=schema)
+```
+
+## OpenAPI Security Checks
+
+| Check | Risk | Severity |
+|-------|------|----------|
+| No request body schema | Injection | HIGH |
+| additionalProperties: true | Mass assignment | MEDIUM |
+| String without maxLength | Buffer overflow | MEDIUM |
+| No response schema | Data exposure | MEDIUM |
+| No security scheme | Broken auth | CRITICAL |
+| Security explicitly disabled | Unauthenticated access | CRITICAL |
+
+## OpenAPI Schema Best Practices
+
+```yaml
+components:
+  schemas:
+    User:
+      type: object
+      additionalProperties: false
+      properties:
+        name:
+          type: string
+          maxLength: 100
+          pattern: "^[a-zA-Z ]+$"
+        email:
+          type: string
+          format: email
+          maxLength: 255
+      required: [name, email]
+```
+
+## Spectral (OpenAPI Linter)
+
+```bash
+spectral lint openapi.yaml --ruleset .spectral.yaml
+# Custom security rules in .spectral.yaml
+```
+
+### References
+
+- jsonschema: https://python-jsonschema.readthedocs.io/
+- OpenAPI 3.0: https://spec.openapis.org/oas/v3.0.3
+- Spectral: https://stoplight.io/open-source/spectral