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/performing-web-cache-poisoning-attack/references/api-reference.md

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+# API Reference: Web Cache Poisoning Attack Agent
+
+## Overview
+
+Tests web applications for cache poisoning vulnerabilities by identifying CDN infrastructure, testing unkeyed headers for reflection and caching, and checking for cache deception paths.
+
+## Dependencies
+
+| Package | Version | Purpose |
+|---------|---------|---------|
+| requests | >= 2.28 | HTTP requests with custom headers |
+
+## Core Functions
+
+### `identify_cache_layer(target_url)`
+Detects caching infrastructure (Cloudflare, Varnish, Akamai, Fastly, CloudFront) from response headers.
+- **Returns**: `dict` with `cdn_detected`, cache headers
+
+### `test_cache_hit_miss(target_url)`
+Sends 3 sequential requests with cache buster to observe HIT/MISS progression.
+- **Returns**: `dict` with per-request cache status
+
+### `test_unkeyed_headers(target_url)`
+Tests 10 common unkeyed headers (X-Forwarded-Host, X-Original-URL, etc.) for reflection and cache poisoning.
+- **Process**: Send header -> check reflection -> re-request without header -> verify cached poison
+- **Returns**: `list[dict]` with `reflected`, `cached_poison`, `risk`
+
+### `test_cache_key_normalization(target_url)`
+Tests cache key handling for extra parameters, fragments, and trailing slashes.
+- **Returns**: `list[dict]` - variation test results
+
+### `test_cache_deception(target_url)`
+Tests web cache deception by requesting authenticated pages with static file extensions (.css, .js, .png).
+- **Returns**: `list[dict]` - cached sensitive endpoints
+
+### `run_assessment(target_url)`
+Full assessment pipeline with summary statistics.
+
+## Unkeyed Headers Tested
+
+| Header | Attack Vector |
+|--------|--------------|
+| X-Forwarded-Host | Host override for poisoning links/redirects |
+| X-Forwarded-Scheme | HTTPS downgrade to HTTP |
+| X-Original-URL | Path override (Nginx/IIS) |
+| X-Rewrite-URL | Path override |
+| X-Host | Alternative host injection |
+| X-Forwarded-Port | Port injection |
+
+## Risk Levels
+
+| Level | Criteria |
+|-------|----------|
+| CRITICAL | Header reflected AND cached (full cache poison) |
+| HIGH | Header reflected but not confirmed cached |
+
+## Usage
+
+```bash
+python agent.py https://target.example.com
+```