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-modbus-command-injection-attacks/SKILL.md

@@ -1,16 +1,29 @@
 ---
 name: detecting-modbus-command-injection-attacks
-description: >
-  Detect command injection attacks against Modbus TCP/RTU protocol in ICS
-  environments by monitoring for unauthorized write operations, anomalous function
-  codes, malformed frames, and deviations from established communication baselines
-  using ICS-aware IDS and protocol deep packet inspection.
+description: 'Detect command injection attacks against Modbus TCP/RTU protocol in ICS environments by monitoring for unauthorized
+  write operations, anomalous function codes, malformed frames, and deviations from established communication baselines using
+  ICS-aware IDS and protocol deep packet inspection.
+
+  '
 domain: cybersecurity
 subdomain: ot-ics-security
-tags: [ot-security, ics, modbus, command-injection, protocol-analysis, ids, scada, threat-detection]
-version: "1.0"
+tags:
+- ot-security
+- ics
+- modbus
+- command-injection
+- protocol-analysis
+- ids
+- scada
+- threat-detection
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.IR-01
+- DE.CM-01
+- ID.AM-05
+- GV.OC-02
 ---
 
 # Detecting Modbus Command Injection Attacks