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-ics-firewall-with-tofino/SKILL.md

@@ -1,16 +1,29 @@
 ---
 name: implementing-ics-firewall-with-tofino
-description: >
-  Deploy and configure Tofino industrial firewalls from Belden/Hirschmann to
-  protect SCADA systems and PLCs using deep packet inspection for OT protocols
-  including Modbus, EtherNet/IP, OPC, and S7comm, enforcing granular access
-  control between ICS security zones.
+description: 'Deploy and configure Tofino industrial firewalls from Belden/Hirschmann to protect SCADA systems and PLCs using
+  deep packet inspection for OT protocols including Modbus, EtherNet/IP, OPC, and S7comm, enforcing granular access control
+  between ICS security zones.
+
+  '
 domain: cybersecurity
 subdomain: ot-ics-security
-tags: [ot-security, ics, firewall, tofino, belden, deep-packet-inspection, network-security, scada]
-version: "1.0"
+tags:
+- ot-security
+- ics
+- firewall
+- tofino
+- belden
+- deep-packet-inspection
+- network-security
+- scada
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.IR-01
+- DE.CM-01
+- ID.AM-05
+- GV.OC-02
 ---
 
 # Implementing ICS Firewall with Tofino