feat: global reusable workflows (workflow_call) + thin caller template

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

.gitea/workflows/reusable-ai-review.yml

@@ -0,0 +1,39 @@
+# GLOBALER, wiederverwendbarer KI-PR-Review (Feature A).
+# Aufruf aus einem beliebigen Repo (siehe workflows/caller.example.yml):
+#   jobs:
+#     review:
+#       if: github.event_name == 'pull_request'
+#       uses: user2595/ci-ai/.gitea/workflows/reusable-ai-review.yml@main
+#       secrets: inherit
+#
+# Voraussetzungen: globaler Runner `eulernest`, anon-Clone für public Repos.
+# Ohne ANTHROPIC_API_KEY überspringt das Skript den KI-Schritt sauber (Job grün).
+name: ci-ai · review (reusable)
+
+on:
+  workflow_call:
+    secrets:
+      ANTHROPIC_API_KEY:
+        required: false
+
+jobs:
+  review:
+    runs-on: eulernest
+    container:
+      image: python:3.12-slim
+      options: "--memory=512m --memory-swap=768m"
+    steps:
+      - name: Tooling (git)
+        run: apt-get update -qq && apt-get install -y -qq --no-install-recommends git ca-certificates
+
+      - name: ci-ai-Skripte holen (anon)
+        run: git clone --depth 1 https://git.eulernest.eu/user2595/ci-ai.git /opt/ci-ai
+
+      - name: KI-Review (überspringt sauber ohne Key)
+        env:
+          AI_PROVIDER: anthropic
+          AI_MODEL: claude-3-5-haiku-latest
+          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
+          GITEA_TOKEN: ${{ github.token }}
+          GITEA_API: https://git.eulernest.eu/api/v1
+        run: python /opt/ci-ai/scripts/ai_review.py