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/performing-threat-intelligence-sharing-with-misp/SKILL.md

@@ -1,12 +1,26 @@
 ---
 name: performing-threat-intelligence-sharing-with-misp
-description: Use PyMISP to create, enrich, and share threat intelligence events on a MISP platform, including IOC management, feed integration, STIX export, and community sharing workflows.
+description: Use PyMISP to create, enrich, and share threat intelligence events on a MISP platform, including IOC management,
+  feed integration, STIX export, and community sharing workflows.
 domain: cybersecurity
 subdomain: threat-intelligence
-tags: [misp, pymisp, threat-intelligence, ioc-sharing, stix, taxii, threat-feeds, information-sharing]
-version: "1.0"
+tags:
+- misp
+- pymisp
+- threat-intelligence
+- ioc-sharing
+- stix
+- taxii
+- threat-feeds
+- information-sharing
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- ID.RA-01
+- ID.RA-05
+- DE.CM-01
+- DE.AE-02
 ---
 # Performing Threat Intelligence Sharing with MISP