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/analyzing-linux-kernel-rootkits/SKILL.md

@@ -1,12 +1,27 @@
 ---
 name: analyzing-linux-kernel-rootkits
-description: Detect kernel-level rootkits in Linux memory dumps using Volatility3 linux plugins (check_syscall, lsmod, hidden_modules), rkhunter system scanning, and /proc vs /sys discrepancy analysis to identify hooked syscalls, hidden kernel modules, and tampered system structures.
+description: Detect kernel-level rootkits in Linux memory dumps using Volatility3 linux plugins (check_syscall, lsmod, hidden_modules),
+  rkhunter system scanning, and /proc vs /sys discrepancy analysis to identify hooked syscalls, hidden kernel modules, and
+  tampered system structures.
 domain: cybersecurity
 subdomain: digital-forensics
-tags: [rootkit, linux, kernel, volatility3, memory-forensics, malware-analysis, rkhunter, forensics]
-version: "1.0"
+tags:
+- rootkit
+- linux
+- kernel
+- volatility3
+- memory-forensics
+- malware-analysis
+- rkhunter
+- forensics
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- RS.AN-01
+- RS.AN-03
+- DE.AE-02
+- RS.MA-01
 ---
 
 # Analyzing Linux Kernel Rootkits