feat(rag): Phase J — Security Guidelines & Standards (NIST, OWASP, ENISA)

Add phase_security() with 15 documents across 3 sub-phases:
- J1: 7 NIST standards (SP 800-53, 800-218, 800-63, 800-207, 8259A/B, AI RMF)
- J2: 6 OWASP projects (Top 10, API Security, ASVS, MASVS, SAMM, Mobile Top 10)
- J3: 2 ENISA guides (Procurement Hospitals, Cloud Security SMEs)

All documents are commercially licensed (Public Domain / CC BY / CC BY-SA).
Wire up 'security' phase in dispatcher and workflow yaml.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/rag-ingest.yaml

@@ -14,7 +14,7 @@ on:
   workflow_dispatch:
     inputs:
       phase:
-        description: 'Ingestion Phase (gesetze, eu, templates, datenschutz, verbraucherschutz, dach, verify, version, all)'
+        description: 'Ingestion Phase (gesetze, eu, templates, datenschutz, verbraucherschutz, dach, security, verify, version, all)'
         required: true
         default: 'verbraucherschutz'