ci: add Gitea Action to auto-reindex KB on markdown push

When .md files are pushed to main, the workflow sends an HMAC-signed
POST to the md-kb-rag webhook on manticore, which triggers git pull
+ incremental re-index of the knowledge base.

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

.gitea/workflows/kb-reindex.yml

@@ -0,0 +1,21 @@
+name: Reindex Knowledge Base
+
+on:
+  push:
+    branches: [main]
+    paths: ['**/*.md']
+
+jobs:
+  reindex:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Trigger KB re-index
+        env:
+          WEBHOOK_SECRET: ${{ secrets.KB_WEBHOOK_SECRET }}
+        run: |
+          BODY='{"ref":"refs/heads/main"}'
+          SIG=$(echo -n "$BODY" | openssl dgst -sha256 -hmac "$WEBHOOK_SECRET" | awk '{print $2}')
+          curl -sf -X POST http://10.10.0.226:8001/hooks/reindex \
+            -H "Content-Type: application/json" \
+            -H "x-gitea-signature: $SIG" \
+            -d "$BODY"