feat(ios): W4 app wiring — DI graph, event fan-out, lifecycle, privacy shade

T-iOS-15: AppEnvironment production DI (real Keychain/probe/transports), EventFanOut
(engine.events → TerminalVM + GateVM + activity bridge), scenePhase lifecycle
(.background→close, suspend→rebuild+reopen reclaims size), privacy shade on != .active,
spike screen deleted, cold-start routing
Walkthrough proxies: hosted live-server smoke over the production DI graph (probe→store→
attach→echo→close) + real-Keychain kSecAttrAccessible assertion (closes T-iOS-7 deferral)
Deviation closed: TerminalViewModel.lastSentDims (valid-only) + alive-engine .active →
notifyForegrounded(dims:) (orchestrator fix on behalf of T-iOS-11 owner)
Env finding: repo under ~/Documents → TCC blocks sim-spawned node; SimServerHarness dual-mode
(self-bootstrap / WEBTERM_SERVER_URL via simctl launchctl setenv)
Verified: 214 pkg + 76 app + 10 integration tests green; verify agent 8/8 PASS

ios/App/WebTerm/WebTermApp.swift

@@ -1,24 +1,15 @@
 import SwiftUI
 
-/// T-iOS-1 scaffold: empty-window placeholder. Navigation assembly
-/// (Pairing → SessionList → Terminal) is wired in T-iOS-15.
+/// T-iOS-15 · App entry: assemble the production dependency graph once and
+/// hand it to the coordinator (Pairing → SessionList → Terminal). All wiring
+/// lives under `Wiring/`; this file stays a thin `@main`.
 @main
 struct WebTermApp: App {
+    @State private var coordinator = AppCoordinator(environment: .production())
+
     var body: some Scene {
         WindowGroup {
-            HelloPlaceholderView()
+            RootView(coordinator: coordinator)
         }
     }
 }
-
-private struct HelloPlaceholderView: View {
-    var body: some View {
-        VStack(spacing: 12) {
-            Image(systemName: "terminal")
-                .font(.largeTitle)
-            Text("Hello WebTerm")
-                .font(.title2)
-        }
-        .padding()
-    }
-}