chore: Add stale agent auditor workflow

.github/workflows/stale-agent-auditor.yml

@@ -0,0 +1,83 @@
+#   Copyright 2025 Google LLC
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+name: ADK Stale Agent Auditor
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 6 * * *'
+
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
+jobs:
+  audit-stale-issues:
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+
+    steps:
+      - name: Generate Token
+        uses: actions/create-github-app-token@v1
+        id: app-token
+        with:
+          app-id: ${{ secrets.APP_ID }}
+          private-key: ${{ secrets.APP_PRIVATE_KEY }}
+          owner: ${{ github.repository_owner }}
+
+      - name: Checkout your repository
+        uses: actions/checkout@v4
+        with:
+          token: ${{ steps.app-token.outputs.token }}
+
+      - name: Fetch Stale Agent Source
+        uses: actions/checkout@v4
+        with:
+          repository: google/adk-python
+          path: external-adk-source
+          sparse-checkout: |
+            contributing/samples/adk_stale_agent
+          sparse-checkout-cone-mode: false
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install uv
+        run: |
+          curl -LsSf https://astral.sh/uv/install.sh | sh
+          echo "$HOME/.cargo/bin" >> $GITHUB_PATH
+
+      - name: Install dependencies
+        run: |
+          uv pip install --system requests "google-adk>=1.27.4"
+
+      - name: Run Stale Agent
+        env:
+          GITHUB_TOKEN: ${{ steps.app-token.outputs.token }}
+          GOOGLE_API_KEY: ${{ secrets.GOOGLE_API_KEY }}
+
+          OWNER: ${{ github.repository_owner }}
+          REPO: ${{ github.event.repository.name }}
+
+          LLM_MODEL_NAME: 'gemini-2.5-flash'
+          STALE_HOURS_THRESHOLD: 72
+          CLOSE_HOURS_AFTER_STALE_THRESHOLD: 96
+
+          PYTHONPATH: external-adk-source/contributing/samples
+
+        run: python -m adk_stale_agent.main