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-secrets-management-with-vault/SKILL.md

@@ -1,17 +1,27 @@
 ---
 name: implementing-secrets-management-with-vault
-description: >
-  This skill covers deploying HashiCorp Vault for centralized secrets management across
-  cloud environments, including dynamic secret generation for databases and cloud providers,
-  transit encryption, PKI certificate management, and Kubernetes integration. It addresses
-  eliminating hardcoded credentials from application code and CI/CD pipelines by implementing
-  short-lived, automatically rotated secrets.
+description: 'This skill covers deploying HashiCorp Vault for centralized secrets management across cloud environments, including
+  dynamic secret generation for databases and cloud providers, transit encryption, PKI certificate management, and Kubernetes
+  integration. It addresses eliminating hardcoded credentials from application code and CI/CD pipelines by implementing short-lived,
+  automatically rotated secrets.
+
+  '
 domain: cybersecurity
 subdomain: cloud-security
-tags: [hashicorp-vault, secrets-management, dynamic-secrets, credential-rotation, zero-trust]
+tags:
+- hashicorp-vault
+- secrets-management
+- dynamic-secrets
+- credential-rotation
+- zero-trust
 version: 1.0.0
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.IR-01
+- ID.AM-08
+- GV.SC-06
+- DE.CM-01
 ---
 
 # Implementing Secrets Management with Vault