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/extracting-browser-history-artifacts/references/api-reference.md

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+# API Reference: Browser History Extraction Agent
+
+## Dependencies
+
+| Library | Version | Purpose |
+|---------|---------|---------|
+| sqlite3 | stdlib | Query Chrome/Firefox SQLite databases |
+| csv | stdlib | Export results to CSV format |
+
+## CLI Usage
+
+```bash
+python scripts/agent.py \
+  --chrome-dir "/mnt/evidence/Users/suspect/AppData/Local/Google/Chrome/User Data/Default" \
+  --firefox-dir "/mnt/evidence/Users/suspect/AppData/Roaming/Mozilla/Firefox/Profiles/abc.default" \
+  --output-dir /cases/analysis/ \
+  --output browser_report.json
+```
+
+## Functions
+
+### `chrome_time_to_utc(chrome_ts) -> str`
+Converts Chrome/WebKit timestamp (microseconds since 1601-01-01) to ISO-8601 UTC string.
+
+### `firefox_time_to_utc(ff_ts) -> str`
+Converts Firefox timestamp (microseconds since Unix epoch) to ISO-8601 UTC string.
+
+### `extract_chrome_history(db_path, limit) -> list`
+Queries the `urls` table from Chrome's `History` SQLite DB. Returns URL, title, last_visit, visit_count.
+
+### `extract_chrome_downloads(db_path, limit) -> list`
+Queries the `downloads` table for file path, source URL, size, timestamps, and danger type.
+
+### `extract_chrome_cookies(db_path, limit) -> list`
+Queries the `cookies` table. Note: cookie values are DPAPI-encrypted on Windows.
+
+### `extract_firefox_history(db_path, limit) -> list`
+Queries `moz_places` JOIN `moz_historyvisits` from Firefox `places.sqlite`.
+
+### `extract_firefox_cookies(db_path, limit) -> list`
+Queries `moz_cookies` from Firefox `cookies.sqlite`.
+
+### `export_to_csv(data, output_path)`
+Writes list of dicts to CSV with headers.
+
+### `generate_report(chrome_dir, firefox_dir, output_dir) -> dict`
+Orchestrates extraction from both browsers and exports CSVs.
+
+## Browser Database Locations (Windows)
+
+| Browser | Path |
+|---------|------|
+| Chrome | `%LOCALAPPDATA%\Google\Chrome\User Data\Default\History` |
+| Edge | `%LOCALAPPDATA%\Microsoft\Edge\User Data\Default\History` |
+| Firefox | `%APPDATA%\Mozilla\Firefox\Profiles\*.default\places.sqlite` |
+
+## Timestamp Formats
+
+| Browser | Epoch | Unit |
+|---------|-------|------|
+| Chrome/Edge | 1601-01-01 | Microseconds |
+| Firefox | 1970-01-01 | Microseconds |