feat: self-hosted LLM backend — point all workflows at the Jetson (Ollama, model=coder)

The Jetson Orin Nano (JetPack 7.2, Ollama on GPU) is live, so ci-ai runs fully
self-hosted: no Anthropic key, no cloud, no per-PR cost. AI_PROVIDER=ollama,
AI_BASE_URL=http://192.168.178.103:11434/v1. The Pi runner reaches it LAN-direct
(SNAT to .48, allowed by the Jetson UFW). Removed the dead ANTHROPIC_API_KEY
secret declarations.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

workflows/security.example.yml

@@ -53,9 +53,9 @@ jobs:
       - name: KI erklärt die Funde (nur bei Fehler, überspringt ohne Key)
         if: failure()
         env:
-          AI_PROVIDER: anthropic
-          AI_MODEL: claude-3-5-haiku-latest
-          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
+          AI_PROVIDER: ollama
+          AI_MODEL: coder
+          AI_BASE_URL: http://192.168.178.103:11434/v1
           GITEA_TOKEN: ${{ github.token }}
           GITEA_API: https://git.eulernest.eu/api/v1
         run: |