Download persistence system revamp

[realdoomsboygaming]

Key Changes

1. Persistence Layer Migration

Replaced all usages of:

• UserDefaults.standard.data(forKey: "downloadedAssets")
• UserDefaults.standard.set(data, forKey: "downloadedAssets")
• Manual array mutation:
  • savedAssets.append(...)
  • savedAssets.removeAll { $0.id == id }

Now uses:

• DownloadPersistence.load()
• DownloadPersistence.save(assets)
• DownloadPersistence.upsert(newAsset)
• DownloadPersistence.delete(id: id)

2. Reactive Downloaded View

• After any download change (add, delete, or update), savedAssets is reloaded from disk.
• objectWillChange.send() is called on the main thread.
• Ensures the Downloaded view and all SwiftUI consumers update immediately.

3. Download Completion Handling

• When a file finishes downloading:
  • The asset is persisted.
  • The UI reflects the new download immediately.

4. Subtitle File Deletion

• Subtitle deletion is now robust:
  • If localSubtitleURL is nil or missing:
    • Searches for files matching the asset’s ID and common subtitle extensions (.vtt, .srt, .webvtt) in the persistent directory.
• Prevents orphaned files and keeps storage clean.

5. General Cleanup

• All legacy persistence logic removed.
• No direct UserDefaults usage remains for downloads.

[cranci1]

You didn't need to send the entire AI resume 😭😭😭