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-hashicorp-vault-dynamic-secrets/references/api-reference.md

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+# API Reference: Implementing HashiCorp Vault Dynamic Secrets
+
+## Libraries
+
+### hvac (HashiCorp Vault Client)
+- **Install**: `pip install hvac`
+- **Docs**: https://hvac.readthedocs.io/en/stable/
+
+## Database Secrets Engine
+
+| Method | Description |
+|--------|-------------|
+| `secrets.database.configure()` | Set up database connection |
+| `secrets.database.create_role()` | Define dynamic credential role |
+| `secrets.database.generate_credentials()` | Generate ephemeral DB credentials |
+| `secrets.database.rotate_root_credentials()` | Rotate root DB password |
+| Plugins: `postgresql-database-plugin`, `mysql-database-plugin`, `mongodb-database-plugin` |
+
+## AWS Secrets Engine
+
+| Method | Description |
+|--------|-------------|
+| `secrets.aws.configure_root_iam_credentials()` | Set AWS root creds |
+| `secrets.aws.create_or_update_role()` | Define IAM role template |
+| `secrets.aws.generate_credentials()` | Generate dynamic IAM keys |
+| Credential types: `iam_user`, `assumed_role`, `federation_token` |
+
+## PKI Secrets Engine
+
+| Method | Description |
+|--------|-------------|
+| `sys.enable_secrets_engine(backend_type="pki")` | Enable PKI |
+| `secrets.pki.generate_root()` | Create CA root certificate |
+| `secrets.pki.create_or_update_role()` | Define cert issuance role |
+| `secrets.pki.generate_certificate()` | Issue dynamic certificate |
+
+## Lease Management
+
+| Method | Description |
+|--------|-------------|
+| `sys.list_leases(prefix)` | List active leases |
+| `sys.revoke_lease(lease_id)` | Revoke specific credential |
+| `sys.revoke_prefix(prefix)` | Revoke all under prefix |
+| `sys.renew_lease(lease_id, increment)` | Extend lease TTL |
+
+## Authentication Methods
+
+| Method | Description |
+|--------|-------------|
+| `auth.token` | Token-based auth |
+| `auth.approle.login()` | AppRole for applications |
+| `auth.kubernetes.login()` | Kubernetes service account |
+| `auth.aws.iam_login()` | AWS IAM-based auth |
+
+## System Operations
+
+| Method | Description |
+|--------|-------------|
+| `sys.read_health_status()` | Vault health check |
+| `sys.list_mounted_secrets_engines()` | List secrets engines |
+| `sys.list_auth_methods()` | List auth backends |
+| `sys.enable_audit_device()` | Enable audit logging |
+
+## External References
+- Vault Documentation: https://developer.hashicorp.com/vault/docs
+- hvac Python Client: https://hvac.readthedocs.io/
+- Database Secrets: https://developer.hashicorp.com/vault/docs/secrets/databases
+- AWS Secrets: https://developer.hashicorp.com/vault/docs/secrets/aws
+- PKI Secrets: https://developer.hashicorp.com/vault/docs/secrets/pki