Enable complete strict concurrency and switch the app target to Swift 6.
- Isolate model dependency protocols to @MainActor
- Make the CoreRepository blocking-FFI bridge race-free: nonisolated(unsafe)
core handle, nonisolated runCore/readSnapshot, @Sendable work block,
Sendable domain models
- Fix Binding method-reference captures; @preconcurrency imports for
CoreNFC/AVFoundation/VnidropCore; isolate the NFC/QR delegate helpers
Add a native SwiftUI VniDrop app (Send/Receive/Settings) talking to the
Rust core via generated UniFFI Swift bindings, plus the uniffi-bindgen
helper crate. iOS uses a TabView, macOS a NavigationSplitView sidebar.
