fix(workmanager_apple): Correct SPM structure and product name for Flutter compatibility

[IwO30]

Summary

This PR fixes Swift Package Manager (SPM) integration with Flutter's plugin system for workmanager_apple.

Problem

Flutter's SPM integration expects:

1. Package.swift at ios/<plugin_name>/Package.swift (not directly in ios/)
2. Product names with hyphens (e.g., workmanager-apple) not underscores (workmanager_apple)

Without these fixes, Flutter falls back to CocoaPods instead of using SPM, even when SPM is enabled.

Changes

• Move Package.swift to ios/workmanager_apple/ subdirectory (Flutter SPM requirement)
• Rename product from workmanager_apple to workmanager-apple (Flutter naming convention)
• Add missing UIKit import in Extensions.swift for UIBackgroundFetchResult
• Move Sources, Resources, Assets to correct subdirectory

Testing

• Tested with Flutter 3.24+ with SPM enabled (flutter config --enable-swift-package-manager)
• iOS build succeeds without CocoaPods fallback
• All 16 iOS plugins now use SPM exclusively

Related

This follows the same pattern as other Flutter plugins with SPM support (e.g., flutter-secure-storage-darwin, path-provider-foundation, etc.)

[docs-page]

To view this pull requests documentation preview, visit the following URL:

docs.page/fluttercommunity/flutter_workmanager~657

Documentation is deployed and generated using docs.page.

[martin-ideeri]

Bump, could we merge this ?

[patrikbadanjak]

I am still getting a warning after implementing this PR as my workmanager dependency that workmanager_apple doesn't support SPM

[IwO30]

@martin-ideeri I'd love to, but I don't have merge rights on this repo — this needs a maintainer to merge. From my side it's ready: all checks pass and there are no conflicts with the base branch.

[IwO30]

@patrikbadanjak The structure in this PR is correct — it matches Flutter's own federated plugins (e.g. path_provider_foundation also uses the hyphenated product name path-provider-foundation with an underscore target). The reason you still see the warning is almost certainly dependency resolution:

The umbrella workmanager package depends on workmanager_apple: ^0.9.1+2, which resolves from pub.dev — i.e. without this fix. So if you only override workmanager to point at this branch, pub still pulls the published workmanager_apple transitively, and the warning stays.

You have to override workmanager_apple explicitly as well:

dependency_overrides:
  workmanager:
    git:
      url: https://github.com/IwO30/flutter_workmanager.git
      ref: fix/spm-product-name-and-structure
      path: workmanager
  workmanager_apple:
    git:
      url: https://github.com/IwO30/flutter_workmanager.git
      ref: fix/spm-product-name-and-structure
      path: workmanager_apple

Then: flutter clean, delete ios/Podfile.lock and ios/.symlinks, run flutter pub get, and rebuild.

Could you confirm whether you had workmanager_apple overridden too? If only workmanager was overridden, that would fully explain the persisting warning.