This is still coming in a little bigger than I would like it to but a lot of the line count is coming from the enums/extensions that are more volume than substance. I'm leaving this in draft for a sec because I'm under the weather this week and want to review this more in depth with a clear head. Primarily I want to look at:

1. Should Metadata & Lock Metadata Sections be two separate views?
2. Does splitting the Pickers into their own files make sense? It makes sense for Language since I can see use reusing that for something like 'Default subtitles' or a feature like that later but I doubt Country will get much use. Finally, I would be amazed if 3DVideoFormatPicker ever gets usages outside this PR.
3. Does the order of the sections/buttons make sense?
4. Is the current switch case for EditMetadataView the best way to do this between ItemTypes or is there a better way to be doing this?

I think this mostly looks good! I've merged this to main and stomped out some of the build issues. I just went through a cleanup an I think there are only items I don't feel super confident in:

1. I found that the notification itemMetadataDidChange was focused around userData. So I made a new one for updating metadata that's just itemId: itemMetadataWasEdited. Since I made this change, this is working really well now!

2. Where I used to pass in a BaseItemDto for the ItemEditorView I am instead passing in the ItemViewModel since this can only be called from ItemView which already has it and this let's me re-use the updating from the ItemView without recreating it unnecessarily.

3. I cleaned up a lot of strings. I've been using Copilot to localize everything and there was a stint where all of my localizations has a redundant 3rd comment. I've just trimmed all my old localizations to match.

4. I made a languagePicker. I'm hoping we can reuse it later for something like "Set default audio language" or "Set default subtitle langauge" so please let me know if there's anything we want to adjust on that to make it more universal.

5. LockMetadata I think it would be good to add an animation for when the other lock options disappear. I just wasn't sure which one to use.

6. ParentalRating works. I'm getting the server's localized ratings which is good but the pickers for it is kind of clunky. Now sure how to make it better and it works so I don't want to blow it up but I'm open to revisions!

@LePips What do you think of something like this as a viewModifier:

//
// Swiftfin is subject to the terms of the Mozilla Public
// License, v2.0. If a copy of the MPL was not distributed with this
// file, you can obtain one at https://mozilla.org/MPL/2.0/.
//
// Copyright (c) 2024 Jellyfin & Jellyfin Contributors
//

import Defaults
import SwiftUI

struct NavigationBarMenuButtonModifier<Content: View>: ViewModifier {

    @Default(.accentColor)
    private var accentColor

    let isLoading: Bool
    let isHidden: Bool
    let items: () -> Content

    func body(content: Self.Content) -> some View {
        content.toolbar {
            ToolbarItemGroup(placement: .topBarTrailing) {

                if isLoading {
                    ProgressView()
                }

                if !isHidden {
                    Menu {
                        items()
                    } label: {
                        Label(L10n.options, systemImage: "ellipsis.circle")
                    }
                    .labelStyle(.iconOnly)
                    .backport
                    .fontWeight(.semibold)
                    .foregroundStyle(accentColor)
                }
            }
        }
    }
}

Since we'll now have this Menu in 3 spots: ItemView, ServerUsersView, and PagingLibraryView. I've included this in the latest commit. The isHidden is specifically so it can work for ServerUsersView where the ... gets replaced by a regular button in editMode. Otherwise, the isLoading is just to avoid the headache of making sure that is consistent throughout usage.

Let me know if you have any changes or if this isn't a good route for this!