feat(ios): 中继通道 P4/P5——端点抽象、信封、传输、配对与分层错误

- InstanceEndpoint 取代 Instance.origin（旧数据 init(from:) 读成 .direct，
  写盘只输出 endpoint；dedupKey 直通用 origin、中继用 relay:<nodeID>）
- RelayWire：Swift 侧重算 contracts/test-vectors.json（CanonicalJSON 手写解析器，
  因为 Foundation 的解码器会抹掉'拼写'，而 intent 摘要定义的正是拼写）
- NodeTransport 抽象 + DirectTransport / RelayTransport / NodeTransportRouter；
  DirectTransport 是薄适配，直通路径行为不变
- RelayTransport：信封构造、签名、加密、验签、解密；响应验签失败即丢弃，
  四类以上失败各有独立 UpstreamError 分支与用户文案
- DeviceIdentity（沙盒文件 0600，配对时由节点分配 deviceID）、RelayPairing、配对 sheet
- 卡片通道徽标 + freshness 副标题；危险写 intent 在发送瞬间生成
- scripts/export-app-routes.swift 生成 vendored 路由表，AppRoutesContractTests 反向守卫
- 测试 78→92：向量互算、迁移（字面量旧 JSON）、配对四类失败、路由器、
  传输往返与各类拒绝路径

apps/ios/Sources/MultiSimAdmin/Features/Logs/LogCenterService.swift

@@ -19,21 +19,25 @@ public struct LogCenterService: Sendable {
         var diagnostic: InstanceDiagnostic?
     }
 
-    private let client: any SimAdminClientProtocol
-    private let sessions: InstanceSessionStore
-    private let credentials: (any CredentialStore)?
+    private let transport: any NodeTransport
     private let store: any LogStore
 
+    public init(transport: any NodeTransport, store: any LogStore) {
+        self.transport = transport
+        self.store = store
+    }
+
+    /// Direct-mode construction, kept for the existing call sites and tests.
     public init(
         client: any SimAdminClientProtocol,
         sessions: InstanceSessionStore,
         credentials: (any CredentialStore)? = nil,
         store: any LogStore
     ) {
-        self.client = client
-        self.sessions = sessions
-        self.credentials = credentials
-        self.store = store
+        self.init(
+            transport: DirectTransport(client: client, sessions: sessions, credentials: credentials),
+            store: store
+        )
     }
 
     public func refresh(_ instances: [Instance]) async throws -> LogSnapshot {
@@ -115,7 +119,11 @@ public struct LogCenterService: Sendable {
     private func probe(_ instance: Instance) async -> ProbeOutcome {
         let startedAt = Date()
         do {
-            let response = try await client.send(.health, baseURL: instance.origin, cookie: nil)
+            let response = try await transport.send(
+                .health,
+                instanceID: instance.id,
+                endpoint: instance.endpoint
+            )
             let duration = elapsed(startedAt)
             let root = (try? JSONSerialization.jsonObject(with: response.data)) as? [String: Any] ?? [:]
             return ProbeOutcome(
@@ -207,7 +215,7 @@ public struct LogCenterService: Sendable {
         return InstanceDiagnostic(
             id: instance.id,
             name: instance.name,
-            origin: instance.origin.absoluteString,
+            origin: instance.endpoint.displayAddress,
             tags: instance.tags,
             state: probe.status,
             healthStatus: Self.healthLabel(probe),
@@ -226,30 +234,7 @@ public struct LogCenterService: Sendable {
     }
 
     private func request(_ route: UpstreamRoute, _ instance: Instance) async throws -> UpstreamResponse {
-        var cookie = await sessions.cookie(for: instance.id, origin: instance.origin)
-        do {
-            return try await client.send(route, baseURL: instance.origin, cookie: cookie)
-        } catch UpstreamError.unauthorized, UpstreamError.forbidden {
-            cookie = try await login(instance)
-            return try await client.send(route, baseURL: instance.origin, cookie: cookie)
-        }
-    }
-
-    private func login(_ instance: Instance) async throws -> String {
-        guard let credentials,
-              let password = try credentials.get(instanceID: instance.id),
-              !password.isEmpty
-        else {
-            throw UpstreamError.unauthorized
-        }
-        let service = InstanceSessionService(store: sessions, client: client)
-        let result = try await service.login(instance, password: password)
-        guard result.authenticated,
-              let cookie = await sessions.cookie(for: instance.id, origin: instance.origin)
-        else {
-            throw UpstreamError.unauthorized
-        }
-        return cookie
+        try await transport.send(route, instanceID: instance.id, endpoint: instance.endpoint)
     }
 
     private func elapsed(_ startedAt: Date) -> Int {