ci: keep Windows Blacksmith testbox ready

.github/workflows/windows-blacksmith-testbox.yml

@@ -123,5 +123,78 @@ jobs:
           git --version
 
       - name: Run Testbox
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          state=/tmp/.testbox
+          test -d "$state"
+
+          testbox_id="$(cat "$state/testbox_id")"
+          installation_model_id="$(cat "$state/installation_model_id")"
+          auth_token="$(cat "$state/auth_token")"
+          idle_timeout="$(cat "$state/idle_timeout" 2>/dev/null || true)"
+          idle_timeout="${idle_timeout:-10}"
+          api_url="$(cat "$state/api_url")"
+          runner_host="$(cat "$state/runner_host")"
+          runner_ssh_port="$(cat "$state/runner_ssh_port")"
+          working_directory="$(cat "$state/working_directory")"
+          adopted_run_id="$(cat "$state/adopted_run_id")"
+
+          ready_body="$RUNNER_TEMP/testbox-ready.json"
+          cat > "$ready_body" <<JSON
+          {
+            "testbox_id": "${testbox_id}",
+            "installation_model_id": ${installation_model_id},
+            "status": "ready",
+            "ip_address": "${runner_host}",
+            "ssh_port": "${runner_ssh_port}",
+            "working_directory": "${working_directory}",
+            "adopted_run_id": "${adopted_run_id}",
+            "metadata": {}
+          }
+          JSON
+
+          http_code="$(curl -sS -o "$RUNNER_TEMP/testbox-ready.response" -w '%{http_code}' \
+            -X POST "${api_url}/api/testbox/phone-home" \
+            -H "Content-Type: application/json" \
+            -H "Authorization: Bearer ${auth_token}" \
+            --data-binary @"$ready_body" || true)"
+          echo "phone_home_ready_http=${http_code}"
+
+          echo "============================================"
+          echo "Testbox ready!"
+          echo "  Testbox ID:         ${testbox_id}"
+          echo "  Runner host:        ${runner_host}"
+          echo "  SSH port:           ${runner_ssh_port}"
+          echo "  Working directory:  ${working_directory}"
+          echo "  Run ID:             ${adopted_run_id}"
+          echo "  SSH:                ssh -p ${runner_ssh_port} runner@${runner_host}"
+          echo "============================================"
+
+          last_activity="$(date +%s)"
+          idle_timeout_seconds=$(( idle_timeout * 60 ))
+
+          while true; do
+            sleep 30
+            now="$(date +%s)"
+
+            if netstat -na 2>/dev/null | grep -q ":${runner_ssh_port}"; then
+              last_activity="$now"
+            elif [ -f ~/.testbox-last-activity ]; then
+              file_mtime="$(stat -c %Y ~/.testbox-last-activity 2>/dev/null || stat -f %m ~/.testbox-last-activity)"
+              if [ "$file_mtime" -gt "$last_activity" ]; then
+                last_activity="$file_mtime"
+              fi
+            fi
+
+            idle_seconds=$(( now - last_activity ))
+            if [ "$idle_seconds" -ge "$idle_timeout_seconds" ]; then
+              echo "Idle timeout reached (${idle_timeout} minutes). Shutting down."
+              exit 0
+            fi
+          done
+
+      - name: Testbox action marker
+        if: ${{ false }}
         uses: useblacksmith/run-testbox@5ca05834db1d3813554d1dd109e5f2087a8d7cbc
-        if: always()