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/deploying-software-defined-perimeter/references/api-reference.md

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+# Software-Defined Perimeter — API Reference
+
+## Core SDP Concepts
+
+| Component | Description |
+|-----------|-------------|
+| SDP Controller | Central policy engine managing authentication and authorization |
+| SDP Gateway | Enforces access policies, terminates encrypted tunnels |
+| SDP Client | End-user agent performing Single Packet Authorization (SPA) |
+| SPA (Single Packet Authorization) | Cryptographic knock before TCP connection allowed |
+
+## Appgate SDP Admin API
+
+| Method | Endpoint | Description |
+|--------|----------|-------------|
+| POST | `/admin/login` | Authenticate and get Bearer token |
+| GET | `/admin/sites` | List configured sites |
+| GET | `/admin/policies` | List access policies |
+| GET | `/admin/entitlements` | List entitlements (resource access rules) |
+| GET | `/admin/appliances` | List SDP gateways and controllers |
+| GET | `/admin/identity-providers` | List identity providers |
+| POST | `/admin/entitlements` | Create new entitlement |
+
+## Dark Port Scanning
+
+```python
+import socket
+sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+sock.settimeout(5)
+result = sock.connect_ex((host, port))  # Non-zero = port dark (SDP enforced)
+```
+
+## Mutual TLS Verification
+
+```python
+import ssl
+ctx = ssl.create_default_context()
+ctx.load_cert_chain("client.crt", "client.key")
+with ctx.wrap_socket(socket.socket(), server_hostname=host) as s:
+    s.connect((host, 443))
+```
+
+## SPA Packet Structure
+
+| Field | Description |
+|-------|-------------|
+| Random Data | 16 bytes of random padding |
+| Username | SDP client identity |
+| Timestamp | Prevents replay attacks |
+| HMAC | SHA-256 authentication code |
+
+## External References
+
+- [Appgate SDP API Docs](https://sdphelp.appgate.com/adminguide/rest-api-guide.html)
+- [CSA SDP Specification](https://cloudsecurityalliance.org/research/sdp/)
+- [fwknop SPA Tool](https://www.cipherdyne.org/fwknop/)