ci(repo): prepare the device image in a background step

Creating and booting the template simulator took four and a half
minutes of waiting in the last full run, and the emulator download up
to three. Both now run as one background step that starts before the
dependency install, and the job waits for it before `up`.

actionlint 1.7.12 predates the `background` and `wait` step keys and
rejects them, so .github/actionlint.yaml ignores its two messages for
this one workflow file, the way clerk_go does for its own. Until
actionlint supports the keys, a step in this file with neither `run`
nor `uses` is not reported either.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: mikepitre

.github/actionlint.yaml

@@ -7,3 +7,13 @@ self-hosted-runner:
   labels:
     - blacksmith-8vcpu-ubuntu-2204
     - blacksmith-6vcpu-macos-26
+
+paths:
+  # actionlint 1.7.x predates GitHub's background steps and rejects them:
+  # https://github.com/rhysd/actionlint/issues/693
+  # Remove once actionlint supports those keys. Until then, a step in this file
+  # with neither `run` nor `uses` is not reported either.
+  .github/workflows/verify-e2e.yml:
+    ignore:
+      - 'unexpected key "background" for step to run shell command'
+      - 'step must run script with "run" section or run action with "uses" section'

.github/workflows/verify-e2e.yml

@@ -93,9 +93,6 @@ jobs:
           node-version: 24.15.0
           cache: ${{ matrix.platform == 'android' && 'pnpm' || '' }}
 
-      - name: Install monorepo dependencies
-        run: pnpm install --frozen-lockfile
-
       - name: Set up JDK 21
         if: matrix.platform == 'android'
         uses: actions/setup-java@cf277c60eb25467037889841efdb72551f06f6c3 # v4
@@ -110,39 +107,41 @@ jobs:
           sudo udevadm control --reload-rules
           sudo udevadm trigger --name-match=kvm
 
-      - name: Install the emulator and its system image
-        if: matrix.platform == 'android'
-        run: |
-          set -euo pipefail
-          IMAGE="system-images;android-36;google_apis;x86_64"
-          for attempt in 1 2 3; do
-            if "$ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager" --install "$IMAGE" emulator platform-tools < /dev/null > "$RUNNER_TEMP/sdkmanager.log" 2>&1; then
-              break
-            fi
-            echo "::warning::sdkmanager could not install $IMAGE on attempt $attempt"
-            grep -v '^\[' "$RUNNER_TEMP/sdkmanager.log" | tail -20 || true
-            if [ "$attempt" = "3" ]; then
-              exit 1
-            fi
-          done
-          echo "$ANDROID_HOME/platform-tools" >> "$GITHUB_PATH"
-
-      - name: Create the template simulator that the skill clones
-        if: matrix.platform == 'ios'
+      - name: Prepare the device image
+        id: device-image
+        background: true
         timeout-minutes: 15
         env:
           IOS_RUNTIME: com.apple.CoreSimulator.SimRuntime.iOS-26-5
         run: |
           set -euo pipefail
-          if ! xcrun simctl list runtimes available -j | jq -e --arg id "$IOS_RUNTIME" '.runtimes[] | select(.identifier == $id)' > /dev/null; then
-            echo "::error::This runner image has no $IOS_RUNTIME. It has: $(xcrun simctl list runtimes available -j | jq -r '[.runtimes[].identifier] | join(", ")')"
-            exit 1
+          if [ "$PLATFORM" = "ios" ]; then
+            if ! xcrun simctl list runtimes available -j | jq -e --arg id "$IOS_RUNTIME" '.runtimes[] | select(.identifier == $id)' > /dev/null; then
+              echo "::error::This runner image has no $IOS_RUNTIME. It has: $(xcrun simctl list runtimes available -j | jq -r '[.runtimes[].identifier] | join(", ")')"
+              exit 1
+            fi
+            udid="$(xcrun simctl create "Clerk Verify Template iOS" "iPhone 17 Pro" "$IOS_RUNTIME")"
+            xcrun simctl boot "$udid"
+            xcrun simctl bootstatus "$udid" -b
+            CLERK_TEST_DEVICES="$udid" integration/tests/expo-native/boot-ios-simulators.sh wait
+            xcrun simctl shutdown "$udid"
+          else
+            IMAGE="system-images;android-36;google_apis;x86_64"
+            for attempt in 1 2 3; do
+              if "$ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager" --install "$IMAGE" emulator platform-tools < /dev/null > "$RUNNER_TEMP/sdkmanager.log" 2>&1; then
+                break
+              fi
+              echo "::warning::sdkmanager could not install $IMAGE on attempt $attempt"
+              grep -v '^\[' "$RUNNER_TEMP/sdkmanager.log" | tail -20 || true
+              if [ "$attempt" = "3" ]; then
+                exit 1
+              fi
+            done
+            echo "$ANDROID_HOME/platform-tools" >> "$GITHUB_PATH"
           fi
-          udid="$(xcrun simctl create "Clerk Verify Template iOS" "iPhone 17 Pro" "$IOS_RUNTIME")"
-          xcrun simctl boot "$udid"
-          xcrun simctl bootstatus "$udid" -b
-          CLERK_TEST_DEVICES="$udid" integration/tests/expo-native/boot-ios-simulators.sh wait
-          xcrun simctl shutdown "$udid"
+
+      - name: Install monorepo dependencies
+        run: pnpm install --frozen-lockfile
 
       - name: Install the verify skill
         id: install
@@ -206,6 +205,9 @@ jobs:
           echo "No native build of this branch is kept for $NATIVE_ID, and the Expo workflow has none for this commit, so this job builds it."
           echo "found=none" >> "$GITHUB_OUTPUT"
 
+      - name: Wait for the device image
+        wait: device-image
+
       - name: Build the fixture and boot a device
         timeout-minutes: 30
         env: