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/securing-historian-server-in-ot-environment/references/api-reference.md

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+# API Reference: Securing Historian Server in OT Environment
+
+## Common Historian Ports
+
+| Port | Service | Risk if Exposed |
+|------|---------|----------------|
+| 5450 | PI Data Archive | SDK/API data access |
+| 5457 | PI AF Server | Asset Framework access |
+| 443 | HTTPS | Web API (acceptable if TLS) |
+| 80 | HTTP | Cleartext credentials/data |
+| 1433 | MS SQL | Direct database queries |
+| 3389 | RDP | Remote admin access |
+| 135/445 | RPC/SMB | Lateral movement target |
+| 502 | Modbus | Industrial protocol |
+
+## Purdue Model Placement
+
+| Level | Systems | Historian Role |
+|-------|---------|---------------|
+| 0-1 | Field devices, PLCs | Data source |
+| 2 | HMI, SCADA | Data source |
+| 3 | Site Operations | OT Historian location |
+| 3.5 | DMZ | Replica historian |
+| 4-5 | Enterprise | Consumer of DMZ data |
+
+## Authentication Methods
+
+| Method | Security Level | Recommendation |
+|--------|---------------|----------------|
+| PI Trust (IP-based) | Insecure | Migrate immediately |
+| piadmin default | Insecure | Disable account |
+| Windows Integrated | Recommended | Use AD groups/PI Mappings |
+| Certificate-based | Strong | For inter-server comms |
+
+## Python Libraries
+
+| Library | Version | Purpose |
+|---------|---------|---------|
+| `socket` | stdlib | Port scanning |
+| `json` | stdlib | Report generation |
+| `pathlib` | stdlib | File handling |
+
+## References
+
+- OSIsoft PI Security Guide: https://docs.aveva.com/
+- IEC 62443: Industrial Automation Security
+- NIST SP 800-82: Guide to ICS Security