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/prioritizing-vulnerabilities-with-cvss-scoring/SKILL.md

@@ -1,12 +1,24 @@
 ---
 name: prioritizing-vulnerabilities-with-cvss-scoring
-description: The Common Vulnerability Scoring System (CVSS) is the industry standard framework maintained by FIRST (Forum of Incident Response and Security Teams) for assessing vulnerability severity. CVSS v4.0 (r
+description: The Common Vulnerability Scoring System (CVSS) is the industry standard framework maintained by FIRST (Forum
+  of Incident Response and Security Teams) for assessing vulnerability severity. CVSS v4.0 (r
 domain: cybersecurity
 subdomain: vulnerability-management
-tags: [vulnerability-management, cve, cvss, risk, prioritization, nist]
-version: "1.0"
+tags:
+- vulnerability-management
+- cve
+- cvss
+- risk
+- prioritization
+- nist
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- ID.RA-01
+- ID.RA-02
+- ID.IM-02
+- ID.RA-06
 ---
 # Prioritizing Vulnerabilities with CVSS Scoring