ci(ios): Hoist snapshot env vars to job level and boot iPad sim separately

Move TEST_RUNNER_SNAPSHOTS_EXPORT_DIR and XCODE_RUNNING_FOR_PREVIEWS into
the job-level env block so both iPhone and iPad test steps share the same
absolute export path. Add a dedicated boot step for the iPad simulator and
clarify the existing boot step name.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: cameroncooke

.github/workflows/ios_sentry_upload_snapshots.yml

@@ -13,6 +13,10 @@ jobs:
       run:
         working-directory: ./ios
 
+    env:
+      TEST_RUNNER_SNAPSHOTS_EXPORT_DIR: "${{ github.workspace }}/ios/snapshot-images"
+      XCODE_RUNNING_FOR_PREVIEWS: 1
+
     steps:
       - name: Checkout
         uses: actions/checkout@v6
@@ -37,12 +41,12 @@ jobs:
           key: ${{ runner.os }}-spm-${{ hashFiles('**/Package.resolved') }}
           restore-keys: ${{ runner.os }}-spm-
 
-      - name: Boot simulator
+      - name: Boot iPhone simulator
         run: xcrun simctl boot "iPhone 17 Pro Max" || true
 
       - name: Generate snapshot images (iPhone)
         run: |
-          set -o pipefail && TEST_RUNNER_SNAPSHOTS_EXPORT_DIR="$PWD/snapshot-images" xcodebuild test \
+          set -o pipefail && xcodebuild test \
             -scheme HackerNews \
             -sdk iphonesimulator \
             -destination 'platform=iOS Simulator,name=iPhone 17 Pro Max' \
@@ -53,9 +57,12 @@ jobs:
             SUPPORTS_MACCATALYST=NO \
             | xcpretty
 
+      - name: Boot iPad simulator
+        run: xcrun simctl boot "iPad Air 11-inch (M3)" || true
+
       - name: Generate snapshot images (iPad)
         run: |
-          set -o pipefail && TEST_RUNNER_SNAPSHOTS_EXPORT_DIR="snapshot-images/" xcodebuild test \
+          set -o pipefail && xcodebuild test \
             -scheme HackerNews \
             -sdk iphonesimulator \
             -destination 'platform=iOS Simulator,name=iPad Air 11-inch (M3)' \