feat: add NIST CSF 2.0 nist_csf field to all 754 cybersecurity skills

Mapped every skill to NIST CSF 2.0 subcategory IDs (GV/ID/PR/DE/RS/RC functions)
based on subdomain and content analysis. Restores 11 skills corrupted during
prior rebase, re-enriching with ATLAS, D3FEND, NIST AI RMF, and CSF 2.0 fields.

All 754 skills now carry structured mappings for all 5 security frameworks:
- MITRE ATT&CK (in tags)
- MITRE ATLAS v5.5 (atlas_techniques)
- MITRE D3FEND v1.3 (d3fend_techniques)
- NIST AI RMF 1.0 (nist_ai_rmf)
- NIST CSF 2.0 (nist_csf)

skills/implementing-ddos-mitigation-with-cloudflare/SKILL.md

@@ -1,12 +1,27 @@
 ---
 name: implementing-ddos-mitigation-with-cloudflare
-description: Configure Cloudflare DDoS protection with managed rulesets, rate limiting, WAF rules, Bot Management, and origin protection to mitigate volumetric, protocol, and application-layer attacks.
+description: Configure Cloudflare DDoS protection with managed rulesets, rate limiting, WAF rules, Bot Management, and origin
+  protection to mitigate volumetric, protocol, and application-layer attacks.
 domain: cybersecurity
 subdomain: network-security
-tags: [ddos, cloudflare, ddos-mitigation, rate-limiting, waf, bot-management, layer-7, volumetric-attack, network-security]
-version: "1.0"
+tags:
+- ddos
+- cloudflare
+- ddos-mitigation
+- rate-limiting
+- waf
+- bot-management
+- layer-7
+- volumetric-attack
+- network-security
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.IR-01
+- DE.CM-01
+- ID.AM-03
+- PR.DS-02
 ---
 
 # Implementing DDoS Mitigation with Cloudflare