initial commit: Proximity iOS app proposal, full Swift code scaffold, reference backend, testing docs, generated Xcode project

Proximity/App/ProximityApp.swift

@@ -0,0 +1,41 @@
+import SwiftUI
+
+@main
+struct ProximityApp: App {
+    @StateObject private var appState = AppState()
+
+    var body: some Scene {
+        WindowGroup {
+            RootView()
+                .environmentObject(appState)
+                .environmentObject(appState.presenceViewModel)
+                .environmentObject(appState.authService)
+                .environmentObject(appState.profileImportService)
+                .environmentObject(appState.revealFlow)
+                .environmentObject(appState.chatViewModel)
+                .environmentObject(appState.realtime)
+        }
+    }
+}
+
+/// Routes between the sign-in flow and the main app based on auth state.
+struct RootView: View {
+    @EnvironmentObject private var appState: AppState
+    @EnvironmentObject private var authService: AuthService
+
+    var body: some View {
+        Group {
+            switch authService.state {
+            case .signedOut:
+                SignInView()
+            case .authenticating:
+                ProgressView("Signing in…")
+            case .authenticated:
+                ContentView()
+            }
+        }
+        .task {
+            await authService.restoreSession()
+        }
+    }
+}