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/building-role-mining-for-rbac-optimization/SKILL.md

@@ -1,12 +1,24 @@
 ---
 name: building-role-mining-for-rbac-optimization
-description: Apply bottom-up and top-down role mining techniques to discover optimal RBAC roles from existing user-permission assignments, reducing role explosion and enforcing least privilege.
+description: Apply bottom-up and top-down role mining techniques to discover optimal RBAC roles from existing user-permission
+  assignments, reducing role explosion and enforcing least privilege.
 domain: cybersecurity
 subdomain: identity-access-management
-tags: [rbac, role-mining, identity-governance, access-control, least-privilege, clustering]
-version: "1.0"
+tags:
+- rbac
+- role-mining
+- identity-governance
+- access-control
+- least-privilege
+- clustering
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.AA-01
+- PR.AA-02
+- PR.AA-05
+- PR.AA-06
 ---
 
 # Building Role Mining for RBAC Optimization