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/exploiting-sql-injection-vulnerabilities/references/api-reference.md

@@ -0,0 +1,60 @@
+# API Reference: SQL Injection Detection Agent
+
+## Dependencies
+
+| Library | Version | Purpose |
+|---------|---------|---------|
+| requests | >=2.28 | HTTP client for injection payload delivery |
+
+## CLI Usage
+
+```bash
+python scripts/agent.py \
+  --url "https://target.example.com/products" \
+  --param id --method GET \
+  --output sqli_report.json
+```
+
+## Functions
+
+### `detect_error_based(url, param, method, headers) -> dict`
+Injects `'` and matches response against SQL error patterns for MySQL, PostgreSQL, MSSQL, Oracle, SQLite.
+
+### `detect_boolean_based(url, param, method, headers) -> dict`
+Compares response lengths for `AND 1=1` (true) vs `AND 1=2` (false) against a baseline.
+
+### `detect_time_based(url, param, method, headers, delay) -> dict`
+Tests `SLEEP()`, `pg_sleep()`, and `WAITFOR DELAY` payloads. Measures response time against target delay.
+
+### `detect_union_columns(url, param, method, headers, max_cols) -> dict`
+Increments `ORDER BY N` until error to determine column count for UNION injection.
+
+### `fingerprint_database(url, param, method, headers) -> dict`
+Tries `@@version` and `version()` via UNION SELECT to identify the database engine.
+
+### `run_assessment(url, param, method) -> dict`
+Runs all detection techniques and compiles findings.
+
+## SQL Error Signatures
+
+| Database | Pattern |
+|----------|---------|
+| MySQL | `SQL syntax.*MySQL`, `Warning.*mysql_` |
+| PostgreSQL | `ERROR:\s+syntax error`, `PSQLException` |
+| MSSQL | `SQL Server.*Driver`, `SQLServerException` |
+| Oracle | `ORA-\d{5}` |
+| SQLite | `SQLite\.Exception` |
+
+## Output Schema
+
+```json
+{
+  "target": "https://target.example.com/products",
+  "parameter": "id",
+  "injectable": true,
+  "error_based": {"injectable": true, "database": "mysql"},
+  "boolean_based": {"injectable": true},
+  "time_based": {"injectable": false},
+  "findings": ["CRITICAL: Error-based SQLi confirmed (DB: mysql)"]
+}
+```