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/investigating-ransomware-attack-artifacts/references/api-reference.md

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+# API Reference: Investigating Ransomware Attack Artifacts
+
+## VirusTotal API v3
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/api/v3/files/{hash}` | GET | Look up ransomware sample by MD5/SHA-256 |
+| `/api/v3/files` | POST | Upload ransomware sample for analysis |
+| `/api/v3/files/{id}/behaviour_summary` | GET | Retrieve behavioral analysis results |
+
+## ID Ransomware
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `https://id-ransomware.malwarehunterteam.com/` | POST | Upload ransom note or encrypted sample for variant ID |
+
+## No More Ransom Project
+
+| Resource | Description |
+|----------|-------------|
+| `https://www.nomoreransom.org/crypto-sheriff.php` | Check if free decryptor is available for identified variant |
+
+## MalwareBazaar API
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `https://mb-api.abuse.ch/api/v1/` | POST | Query ransomware samples by hash, tag, or signature |
+
+## Key Libraries
+
+- **requests**: HTTP client for VirusTotal and ID Ransomware API calls
+- **hashlib** (stdlib): Calculate MD5/SHA-256 hashes of ransomware samples and notes
+- **re** (stdlib): Extract Bitcoin addresses, Tor .onion sites, and emails from notes
+- **csv** (stdlib): Parse exported Windows Event Log data
+- **pathlib** (stdlib): Recursive file system traversal for artifact discovery
+
+## Ransomware IOC Patterns
+
+| Pattern | Regex | Description |
+|---------|-------|-------------|
+| Bitcoin | `[13][a-km-zA-HJ-NP-Z1-9]{25,34}` | Legacy Bitcoin addresses |
+| Bitcoin Bech32 | `bc1[a-z0-9]{39,59}` | SegWit Bitcoin addresses |
+| Monero | `4[0-9AB][1-9A-HJ-NP-Za-km-z]{93}` | Monero wallet addresses |
+| Tor Sites | `[a-z2-7]{16,56}\.onion` | Tor hidden service domains |
+
+## Configuration
+
+| Variable | Description |
+|----------|-------------|
+| `VT_API_KEY` | VirusTotal API key for hash lookups and sample submission |
+
+## References
+
+- [ID Ransomware](https://id-ransomware.malwarehunterteam.com/)
+- [No More Ransom Project](https://www.nomoreransom.org/)
+- [CISA Stop Ransomware](https://www.cisa.gov/stopransomware)
+- [VirusTotal API v3](https://docs.virustotal.com/reference/overview)