fix(ios): download specific runtime version instead of latest

Pass -buildVersion to xcodebuild -downloadPlatform so it downloads the
exact runtime version requested by the device definition (e.g., iOS 26.3)
rather than whatever is latest for the current Xcode (e.g., iOS 26.4).

This was causing iOS E2E failures on runners with Xcode 26.4, which only
ships with the iOS 26.4 beta runtime. The download command would fetch
26.4 again instead of the requested 26.3 stable runtime.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: abueide

plugins/ios/virtenv/scripts/domain/device_manager.sh

@@ -74,14 +74,14 @@ resolve_runtime() {
   fi
 
   if [ "${IOS_DOWNLOAD_RUNTIME:-1}" != "0" ] && command -v xcodebuild >/dev/null 2>&1; then
-    echo "Preferred runtime iOS ${preferred} not found. Attempting to download via xcodebuild -downloadPlatform iOS..." >&2
-    if xcodebuild -downloadPlatform iOS; then
+    echo "Preferred runtime iOS ${preferred} not found. Attempting to download via xcodebuild -downloadPlatform iOS -buildVersion ${preferred}..." >&2
+    if xcodebuild -downloadPlatform iOS -buildVersion "$preferred"; then
       if choice="$(pick_runtime "$preferred")"; then
         printf '%s\n' "$choice"
         return 0
       fi
     else
-      echo "xcodebuild -downloadPlatform iOS failed; continuing with available runtimes." >&2
+      echo "xcodebuild -downloadPlatform iOS -buildVersion ${preferred} failed; continuing with available runtimes." >&2
     fi
   fi
 
@@ -99,14 +99,14 @@ resolve_runtime_strict() {
   fi
 
   if [ "${IOS_DOWNLOAD_RUNTIME:-1}" != "0" ] && command -v xcodebuild >/dev/null 2>&1; then
-    echo "Preferred runtime iOS ${preferred} not found. Attempting to download via xcodebuild -downloadPlatform iOS..." >&2
-    if xcodebuild -downloadPlatform iOS; then
+    echo "Preferred runtime iOS ${preferred} not found. Attempting to download via xcodebuild -downloadPlatform iOS -buildVersion ${preferred}..." >&2
+    if xcodebuild -downloadPlatform iOS -buildVersion "$preferred"; then
       if choice="$(pick_runtime_strict "$preferred")"; then
         printf '%s\n' "$choice"
         return 0
       fi
     else
-      echo "xcodebuild -downloadPlatform iOS failed." >&2
+      echo "xcodebuild -downloadPlatform iOS -buildVersion ${preferred} failed." >&2
     fi
   fi