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/triaging-security-alerts-in-splunk/SKILL.md

@@ -1,17 +1,29 @@
 ---
 name: triaging-security-alerts-in-splunk
-description: >
-  Triages security alerts in Splunk Enterprise Security by classifying severity, investigating
-  notable events, correlating related telemetry, and making escalation or closure decisions using
-  SPL queries and the Incident Review dashboard. Use when SOC analysts face queued alerts from
-  correlation searches, need to prioritize investigation order, or must document triage decisions
-  for handoff to Tier 2/3 analysts.
+description: 'Triages security alerts in Splunk Enterprise Security by classifying severity, investigating notable events,
+  correlating related telemetry, and making escalation or closure decisions using SPL queries and the Incident Review dashboard.
+  Use when SOC analysts face queued alerts from correlation searches, need to prioritize investigation order, or must document
+  triage decisions for handoff to Tier 2/3 analysts.
+
+  '
 domain: cybersecurity
 subdomain: soc-operations
-tags: [soc, splunk, alert-triage, siem, notable-events, correlation-search, incident-review]
-version: "1.0"
+tags:
+- soc
+- splunk
+- alert-triage
+- siem
+- notable-events
+- correlation-search
+- incident-review
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- DE.CM-01
+- DE.AE-02
+- RS.MA-01
+- DE.AE-06
 ---
 # Triaging Security Alerts in Splunk