ci: reset stale CocoaPods trunk repo on Xcode Cloud workers

ios/ci_scripts/ci_post_clone.sh

@@ -16,6 +16,18 @@ brew install yarn
 # Install dependencies
 echo "===== Running yarn install ====="
 yarn install
+
+# Reset stale CocoaPods spec-repo state from cached Xcode Cloud worker
+# images. The Homebrew CocoaPods 1.16+ wants the trunk source registered
+# as a CDN, but a pre-existing `~/.cocoapods/repos/trunk` from older
+# installs makes `pod install` abort with:
+#   [!] Unable to add a source with url `https://cdn.cocoapods.org/`
+#       named `trunk`.
+# Wiping the dir and explicitly registering the CDN source up front
+# makes the install path deterministic on every run.
+rm -rf "$HOME/.cocoapods/repos/trunk" 2>/dev/null || true
+pod repo add-cdn trunk https://cdn.cocoapods.org/ 2>/dev/null || true
+
 echo "===== Running pod install ====="
 cd ios
 pod install