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/configuring-identity-aware-proxy-with-google-iap/SKILL.md

@@ -1,15 +1,28 @@
 ---
 name: configuring-identity-aware-proxy-with-google-iap
-description: >
-  Configuring Google Cloud Identity-Aware Proxy (IAP) to enforce per-request identity
-  verification for Compute Engine, App Engine, Cloud Run, and GKE services using
-  access levels, context-aware policies, and programmatic access with service accounts.
+description: 'Configuring Google Cloud Identity-Aware Proxy (IAP) to enforce per-request identity verification for Compute
+  Engine, App Engine, Cloud Run, and GKE services using access levels, context-aware policies, and programmatic access with
+  service accounts.
+
+  '
 domain: cybersecurity
 subdomain: zero-trust-architecture
-tags: [google-iap, identity-aware-proxy, gcp, zero-trust, access-context-manager, cloud-run, app-engine]
-version: "1.0"
+tags:
+- google-iap
+- identity-aware-proxy
+- gcp
+- zero-trust
+- access-context-manager
+- cloud-run
+- app-engine
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.AA-01
+- PR.AA-05
+- PR.IR-01
+- GV.PO-01
 ---
 
 # Configuring Identity-Aware Proxy with Google IAP