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-attack-path-analysis-with-xm-cyber/SKILL.md

@@ -1,12 +1,25 @@
 ---
 name: implementing-attack-path-analysis-with-xm-cyber
-description: Deploy XM Cyber's continuous exposure management platform to map attack paths, identify choke points, and prioritize the 2% of exposures that threaten critical assets.
+description: Deploy XM Cyber's continuous exposure management platform to map attack paths, identify choke points, and prioritize
+  the 2% of exposures that threaten critical assets.
 domain: cybersecurity
 subdomain: vulnerability-management
-tags: [xm-cyber, attack-path-analysis, exposure-management, ctem, choke-points, breach-simulation, attack-surface]
-version: "1.0"
+tags:
+- xm-cyber
+- attack-path-analysis
+- exposure-management
+- ctem
+- choke-points
+- breach-simulation
+- attack-surface
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- ID.RA-01
+- ID.RA-02
+- ID.IM-02
+- ID.RA-06
 ---
 # Implementing Attack Path Analysis with XM Cyber