Cut+paste an embedded image loses the id, then breaks permanently

[jshirley]

(I think there is some overlap with #57 but I am very new to this package so may just be 100% wrong!)

I'm building an opinionated desktop app to track development logs, and using SwiftMarkdownEngine for the content. A big part of the workflow is tracking screenshots/recordings. When I add an image, I get the expected ![[simulator_screenshot_51AB8961-73FD-46B4-A50F-0A285146BF90.png]] text and it previews correctly. If I move that to a different part in the document, the UUID doesn't get carried along with it and the embed breaks permanently.

I leaned on Claude to get a minimal repro, but I think it's accurate:

import SwiftUI
import MarkdownEngine

private let fixedID = UUID(uuidString: "11111111-1111-1111-1111-111111111111")!

struct ReproImageProvider: EmbeddedImageProvider {
    func image(for reference: EmbeddedImageRequest) -> NSImage? {
        guard reference.id == fixedID.uuidString else { return nil }
        let image = NSImage(size: NSSize(width: 40, height: 40))
        image.lockFocus()
        NSColor.systemRed.setFill()
        NSRect(x: 0, y: 0, width: 40, height: 40).fill()
        image.unlockFocus()
        return image
    }
    func fingerprint() -> AnyHashable { 0 }
}

struct ReproView: View {
    @State private var text = "![[photo|\(fixedID.uuidString)]]\n\nSome other paragraph."

    var body: some View {
        NativeTextViewWrapper(
            text: $text,
            configuration: .init(services: .init(images: ReproImageProvider())),
            documentId: "repro"
        )
    }
}

1. Run ReproView. The red square should render in place of ![[photo|11111111-...]].
2. Select the entire line containing the embed and press Cmd+X to cut.
3. After "Some other paragraph." paste (Cmd+V)

Now instead of a red square, should render ![[photo|11111...]] rather than the red square and it can't resolve to a matching id anymore.

Happy to help more with a bit of guidance and confirmation!