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/detecting-email-account-compromise/SKILL.md

@@ -1,13 +1,30 @@
 ---
 name: detecting-email-account-compromise
-description: Detect compromised O365 and Google Workspace email accounts by analyzing inbox rule creation, suspicious sign-in locations, mail forwarding rules, and unusual API access patterns via Microsoft Graph and audit logs.
+description: Detect compromised O365 and Google Workspace email accounts by analyzing inbox rule creation, suspicious sign-in
+  locations, mail forwarding rules, and unusual API access patterns via Microsoft Graph and audit logs.
 domain: cybersecurity
 subdomain: incident-response
-tags: [email-compromise, office365, microsoft-graph, bec, inbox-rules, sign-in-analysis, account-takeover]
-mitre_attack: ["T1114", "T1566", "T1078", "T1534"]
-version: "1.0"
+tags:
+- email-compromise
+- office365
+- microsoft-graph
+- bec
+- inbox-rules
+- sign-in-analysis
+- account-takeover
+mitre_attack:
+- T1114
+- T1566
+- T1078
+- T1534
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- RS.MA-01
+- RS.MA-02
+- RS.AN-03
+- RC.RP-01
 ---
 # Detecting Email Account Compromise