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/Wiring/TerminalContainerView.swift

@@ -0,0 +1,103 @@
+import SessionCore
+import SwiftUI
+
+/// T-iOS-15 · Terminal destination view: TerminalScreen (T-iOS-11) plus the
+/// gate/digest surfaces (T-iOS-14) wired to the controller's GateViewModel —
+/// the "接入 TerminalScreen 的 wiring 归 T-iOS-15" hand-off.
+///
+/// Layout decisions (documented):
+/// - `.id(controller.generation)`: a rebuild (background→foreground) swaps the
+///   ViewModels; without a new identity SwiftUI would keep the old UIView and
+///   `makeUIView` (where the output sink attaches) would never run again.
+/// - Digest + tool-gate banner live in a TOP overlay stack: the bottom edge
+///   belongs to the keyboard + key bar. TerminalScreen's own ReconnectBanner
+///   is also top-aligned, but it hides on `.connected` while gates/digests
+///   only arrive connected — practical overlap is nil.
+/// - Plan gate presents as a medium-detent sheet; swiping it away is allowed
+///   (the user may need to scroll the terminal to read the plan), and a
+///   "计划待批" re-entry chip appears until the gate resolves. Deciding
+///   removes the gate server-side → `planGate` goes nil → sheet dismisses.
+struct TerminalContainerView: View {
+    let controller: TerminalSessionController
+    /// Epoch of a plan gate the user swiped away — suppresses re-present for
+    /// THAT gate only; a new epoch re-presents automatically.
+    @State private var dismissedPlanGateEpoch: Int?
+
+    private enum Metrics {
+        static let overlaySpacing: CGFloat = 8
+        static let overlayHorizontalPadding: CGFloat = 12
+        /// Clears TerminalScreen's own top-aligned ReconnectBanner zone.
+        static let overlayTopPadding: CGFloat = 52
+    }
+
+    private enum Copy {
+        static let planGatePending = "⚠ 计划待批准"
+    }
+
+    var body: some View {
+        TerminalScreen(viewModel: controller.terminalViewModel)
+            .id(controller.generation)
+            .navigationBarTitleDisplayMode(.inline)
+            .overlay(alignment: .top) { topOverlays }
+            .sheet(isPresented: planGateBinding) { planGateSheet }
+    }
+
+    // MARK: - Digest + tool gate (top stack)
+
+    @ViewBuilder private var topOverlays: some View {
+        let gateViewModel = controller.gateViewModel
+        VStack(spacing: Metrics.overlaySpacing) {
+            if let digest = gateViewModel.digest {
+                AwayDigestView(
+                    digest: digest,
+                    isExpanded: gateViewModel.isDigestExpanded,
+                    onExpand: { gateViewModel.expandDigest() },
+                    onDismiss: { gateViewModel.dismissDigest() }
+                )
+            }
+            if let gate = gateViewModel.toolGate {
+                GateBanner(gate: gate) { affordance, epoch in
+                    gateViewModel.decide(affordance, epoch: epoch)
+                }
+            }
+            if hasDismissedPendingPlanGate {
+                Button(Copy.planGatePending) { dismissedPlanGateEpoch = nil }
+                    .buttonStyle(.borderedProminent)
+                    .tint(.orange)
+                    .controlSize(.small)
+            }
+        }
+        .padding(.horizontal, Metrics.overlayHorizontalPadding)
+        .padding(.top, Metrics.overlayTopPadding)
+        .animation(.default, value: gateViewModel.toolGate)
+        .animation(.default, value: gateViewModel.digest)
+    }
+
+    // MARK: - Plan gate sheet
+
+    private var hasDismissedPendingPlanGate: Bool {
+        guard let gate = controller.gateViewModel.planGate else { return false }
+        return gate.epoch == dismissedPlanGateEpoch
+    }
+
+    private var planGateBinding: Binding<Bool> {
+        Binding(
+            get: {
+                guard let gate = controller.gateViewModel.planGate else { return false }
+                return gate.epoch != dismissedPlanGateEpoch
+            },
+            set: { presented in
+                guard !presented else { return }
+                dismissedPlanGateEpoch = controller.gateViewModel.planGate?.epoch
+            }
+        )
+    }
+
+    @ViewBuilder private var planGateSheet: some View {
+        if let gate = controller.gateViewModel.planGate {
+            PlanGateSheet(gate: gate) { affordance, epoch in
+                controller.gateViewModel.decide(affordance, epoch: epoch)
+            }
+        }
+    }
+}