ci: regenerate Podfile.lock for legacy iOS pod install

The committed lock is experimental-generated; the legacy backend re-resolve rejected the stale external fast_float checksum. Remove the lock before the legacy pod install so it resolves fresh.

Author: mfazekas

.github/workflows/ci.yml

@@ -507,6 +507,11 @@ jobs:
         run: |
           cd example
           bundle install
+          # The committed Podfile.lock is generated for the experimental backend.
+          # Removing it lets the legacy backend resolve its own dependency graph;
+          # otherwise the external fast_float podspec checksum mismatches and
+          # pod install fails ("could not find compatible versions for fast_float").
+          rm -f ios/Podfile.lock ios/Pods/Manifest.lock
           USE_RIVE_LEGACY=1 bundle exec pod install --project-directory=ios
 
       - name: Save cocoapods cache