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/performing-blind-ssrf-exploitation/SKILL.md

@@ -1,12 +1,25 @@
 ---
 name: performing-blind-ssrf-exploitation
-description: Detect and exploit blind Server-Side Request Forgery vulnerabilities using out-of-band techniques, DNS interactions, and timing analysis to access internal services and cloud metadata endpoints.
+description: Detect and exploit blind Server-Side Request Forgery vulnerabilities using out-of-band techniques, DNS interactions,
+  and timing analysis to access internal services and cloud metadata endpoints.
 domain: cybersecurity
 subdomain: web-application-security
-tags: [blind-ssrf, ssrf, out-of-band, burp-collaborator, cloud-metadata, internal-network, oob-detection]
-version: "1.0"
+tags:
+- blind-ssrf
+- ssrf
+- out-of-band
+- burp-collaborator
+- cloud-metadata
+- internal-network
+- oob-detection
+version: '1.0'
 author: mahipal
 license: Apache-2.0
+nist_csf:
+- PR.PS-01
+- ID.RA-01
+- PR.DS-10
+- DE.CM-01
 ---
 
 # Performing Blind SSRF Exploitation