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/implementing-opa-gatekeeper-for-policy-enforcement/references/api-reference.md

@@ -0,0 +1,46 @@
+# API Reference: OPA Gatekeeper Policy Enforcement
+
+## OPA REST API (localhost:8181)
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/v1/data/{path}` | GET/POST | Query policy |
+| `/v1/policies/{id}` | PUT | Create/update policy |
+| `/v1/data` | POST | Evaluate input against policy |
+
+## Gatekeeper CRDs
+
+| CRD | Description |
+|-----|-------------|
+| `ConstraintTemplate` | Define policy schema + Rego |
+| `Constraint` | Instantiate a template |
+| `Config` | Audit/sync configuration |
+
+## ConstraintTemplate Example
+```yaml
+apiVersion: templates.gatekeeper.sh/v1
+kind: ConstraintTemplate
+metadata:
+  name: k8srequiredlabels
+spec:
+  crd:
+    spec:
+      names:
+        kind: K8sRequiredLabels
+  targets:
+    - target: admission.k8s.gatekeeper.sh
+      rego: |
+        package k8srequiredlabels
+        violation[{"msg": msg}] {
+          not input.review.object.metadata.labels["app"]
+          msg := "Missing required label: app"
+        }
+```
+
+## Key Libraries
+
+| Library | Use |
+|---------|-----|
+| `kubernetes` | K8s API client |
+| `requests` | OPA REST queries |
+| `subprocess` | kubectl commands |