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-zero-trust-with-hashicorp-boundary/SKILL.md

@@ -1,12 +1,26 @@
 ---
 name: implementing-zero-trust-with-hashicorp-boundary
-description: Implement HashiCorp Boundary for identity-aware zero trust infrastructure access management with dynamic credential brokering, session recording, and Vault integration.
+description: Implement HashiCorp Boundary for identity-aware zero trust infrastructure access management with dynamic credential
+  brokering, session recording, and Vault integration.
 domain: cybersecurity
 subdomain: zero-trust-architecture
-tags: [zero-trust, hashicorp, boundary, privileged-access, vault, identity-aware-proxy, session-recording, just-in-time-access]
-version: "1.0"
+tags:
+- zero-trust
+- hashicorp
+- boundary
+- privileged-access
+- vault
+- identity-aware-proxy
+- session-recording
+- just-in-time-access
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.AA-01
+- PR.AA-05
+- PR.IR-01
+- GV.PO-01
 ---
 
 # Implementing Zero Trust with HashiCorp Boundary