fix: pin Xcode 26.0 and simulator runtime for iOS CI

Select Xcode 26.0 and download the iOS simulator runtime before
building. Pin the simulator destination to OS=26.0.1 to match.

This aims to fix sporadic issues where the sim cannot be found on the runner.

Author: microbit-matt-hillsdon

.github/workflows/ci.yml

@@ -88,6 +88,14 @@ jobs:
   verify-ios:
     runs-on: macos-latest
     steps:
+      - name: Select Xcode
+        run: sudo xcode-select --switch /Applications/Xcode_26.0.app
+
+      - name: Prepare simulator runtime
+        run: |
+          xcrun simctl list > /dev/null
+          xcodebuild -downloadPlatform iOS
+
       - name: Checkout
         uses: actions/checkout@v4
         with:

package.json

@@ -40,7 +40,7 @@
   },
   "scripts": {
     "verify": "npm run verify:ios && npm run verify:android && npm run verify:web",
-    "verify:ios": "set -o pipefail && cd ios && pod install && xcodebuild clean build test -workspace Plugin.xcworkspace -scheme Plugin -destination \"platform=iOS Simulator,name=iPhone 17\" | xcpretty && cd ..",
+    "verify:ios": "set -o pipefail && cd ios && pod install && xcodebuild clean build test -workspace Plugin.xcworkspace -scheme Plugin -destination \"platform=iOS Simulator,name=iPhone 17,OS=26.0.1\" | xcpretty && cd ..",
     "verify:android": "cd android && ./gradlew clean build test && cd ..",
     "verify:web": "npm run build",
     "lint": "npm run eslint && npm run prettier -- --check && npm run lint:ios",