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/ViewModels/TerminalViewModel.swift

@@ -43,12 +43,25 @@ final class TerminalViewModel {
         case exited(code: Int, reason: String?)
     }
 
+    /// Terminal geometry snapshot (Equatable for test assertions; the frozen
+    /// engine API takes a tuple, so `asTuple` bridges).
+    struct TerminalDims: Equatable, Sendable {
+        let cols: Int
+        let rows: Int
+        var asTuple: (cols: Int, rows: Int) { (cols, rows) }
+    }
+
     /// Actionable copy for `.failed(.replayTooLarge)` (plan §3.2 / §3.2.1
     /// coupling warning): reconnecting would deterministically fail forever,
     /// so the user must change a knob, not wait.
     static let replayTooLargeMessage =
         "服务器 scrollback 超过客户端上限，请调低 SCROLLBACK_BYTES 或调高客户端上限"
 
+    /// Last VALID dims forwarded to the engine (SwiftTerm `sizeChanged`).
+    /// Read by the wiring layer for `notifyForegrounded(dims:)` — the frozen
+    /// §3.2 signature needs real cols/rows and this is their single source.
+    private(set) var lastSentDims: TerminalDims?
+
     private(set) var banner: ConnectionBanner = .none
     private(set) var phase: TerminalPhase = .live
     /// Server-adopted session id (ALWAYS the server-issued one — persisting it
@@ -182,8 +195,14 @@ final class TerminalViewModel {
     }
 
     /// Terminal geometry changed (SwiftTerm `sizeChanged`). Always forwarded —
-    /// the engine validates bounds and owns terminal-state dropping.
+    /// the engine validates bounds and owns terminal-state dropping. Valid
+    /// dims are remembered in `lastSentDims` so the T-iOS-15 wiring can feed
+    /// `engine.notifyForegrounded(dims:)` on scenePhase reactivation (closes
+    /// the W4 documented deviation; invalid dims never overwrite a good pair).
     func sendResize(cols: Int, rows: Int) {
+        if Validation.isValidResize(cols: cols, rows: rows) {
+            lastSentDims = TerminalDims(cols: cols, rows: rows)
+        }
         enqueueSend(.resize(cols: cols, rows: rows))
     }