feat(ios): W0 scaffold + day-1 spike + WireProtocol frozen contract + TestSupport doubles

T-iOS-1: ios/ XcodeGen project (iOS 17, Swift 6 strict concurrency, ATS per PLAN §5.2), 5 SPM package shells, CI skeleton
T-iOS-2: Origin spike vs real server — URLSessionWebSocketTask custom Origin CONFIRMED (no Starscream); 16MiB replay + EMSGSIZE(40) errno correction written back to plan
T-iOS-3: WireProtocol frozen contract, 59 tests, 100% line coverage, cross-impl vectors vs src/protocol.ts via tsx
T-iOS-4: FakeTransport/FakeClock/FakeHTTPTransport doubles
Verify: independent agent re-ran all acceptance — 6/6 PASS

ios/Packages/TestSupport/Tests/TestSupportTests/FakeHTTPTransportTests.swift

@@ -0,0 +1,42 @@
+import Foundation
+import Testing
+@testable import TestSupport
+
+@Suite("FakeHTTPTransport")
+struct FakeHTTPTransportTests {
+    private static let originValue = "http://192.168.1.5:3000"
+
+    @Test("replays queued responses per URL/method, records requests with headers, and fails loudly when unqueued")
+    func replaysQueuedResponsesAndRecordsRequests() async throws {
+        // Arrange
+        let transport = FakeHTTPTransport()
+        let listURL = try #require(URL(string: "http://192.168.1.5:3000/live-sessions"))
+        let unqueuedURL = try #require(URL(string: "http://192.168.1.5:3000/other"))
+        let body = Data("[]".utf8)
+        await transport.queueSuccess(url: listURL, body: body)
+
+        var request = URLRequest(url: listURL)
+        request.httpMethod = "GET"
+        request.setValue(Self.originValue, forHTTPHeaderField: "Origin")
+
+        // Act
+        let (data, response) = try await transport.send(request)
+
+        // Assert: the queued response came back for that URL/method.
+        #expect(data == body)
+        #expect(response.statusCode == FakeHTTPTransport.defaultOKStatus)
+        #expect(response.url == listURL)
+
+        // Assert: the request was recorded verbatim, headers included
+        // (this is what lets APIClient tests assert Origin-iff-G, plan §3.4).
+        let recorded = await transport.recordedRequests
+        #expect(recorded.count == 1)
+        #expect(recorded.first?.url == listURL)
+        #expect(recorded.first?.value(forHTTPHeaderField: "Origin") == Self.originValue)
+
+        // Assert: an unqueued route throws an explicit, identifying error.
+        await #expect(throws: FakeHTTPTransportError.noQueuedResponse(method: "GET", url: unqueuedURL)) {
+            _ = try await transport.send(URLRequest(url: unqueuedURL))
+        }
+    }
+}