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-privileged-access-workstation/SKILL.md

@@ -1,12 +1,24 @@
 ---
 name: implementing-privileged-access-workstation
-description: Design and implement Privileged Access Workstations (PAWs) with device hardening, just-in-time access, and integration with CyberArk or BeyondTrust for secure administrative operations.
+description: Design and implement Privileged Access Workstations (PAWs) with device hardening, just-in-time access, and integration
+  with CyberArk or BeyondTrust for secure administrative operations.
 domain: cybersecurity
 subdomain: identity-and-access-management
-tags: [privileged-access, PAW, zero-trust, device-hardening, CyberArk, BeyondTrust, just-in-time-access]
-version: "1.0"
+tags:
+- privileged-access
+- PAW
+- zero-trust
+- device-hardening
+- CyberArk
+- BeyondTrust
+- just-in-time-access
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.AA-01
+- PR.AA-02
+- PR.AA-05
 ---
 
 # Implementing Privileged Access Workstation