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-zero-trust-network-access-with-zscaler/references/api-reference.md

@@ -0,0 +1,51 @@
+# API Reference: Zscaler Private Access (ZPA)
+
+## ZPA Management API
+
+### Authentication
+```
+POST https://config.private.zscaler.com/signin
+Body: client_id=X&client_secret=Y
+Returns: {"access_token": "...", "token_type": "Bearer"}
+```
+
+### Application Segments
+| Method | Endpoint | Description |
+|--------|----------|-------------|
+| GET | `/mgmtconfig/v1/admin/customers/{id}/application` | List app segments |
+| POST | `/mgmtconfig/v1/admin/customers/{id}/application` | Create app segment |
+
+### Server Groups
+| Method | Endpoint | Description |
+|--------|----------|-------------|
+| GET | `/mgmtconfig/v1/admin/customers/{id}/serverGroup` | List server groups |
+
+### Access Policies
+| Method | Endpoint | Description |
+|--------|----------|-------------|
+| GET | `/mgmtconfig/v1/admin/customers/{id}/policySet/rules` | List policy rules |
+
+### Connectors
+| Method | Endpoint | Description |
+|--------|----------|-------------|
+| GET | `/mgmtconfig/v1/admin/customers/{id}/connector` | List connectors |
+
+### App Segment Fields
+| Field | Description |
+|-------|-------------|
+| `name` | Application segment name |
+| `enabled` | Whether segment is active |
+| `bypassType` | `NEVER`, `ALWAYS`, or `ON_NET` |
+| `domainNames` | FQDN list for the segment |
+| `tcpPortRanges` | Allowed TCP port ranges |
+
+### Bypass Types
+| Value | Security Implication |
+|-------|---------------------|
+| `NEVER` | Always enforce ZPA (recommended) |
+| `ALWAYS` | Bypass ZPA entirely (high risk) |
+| `ON_NET` | Bypass when on corporate network |
+
+## References
+- ZPA API: https://help.zscaler.com/zpa/about-zpa-api
+- ZPA Admin Guide: https://help.zscaler.com/zpa