完善 OTG 相机有线传图：支持 Sony/Canon 自动识别，页面 detach 保持会话以便再次进入复连。

引入进程级 CameraTetheringSession 与共享 USB Browser；离开传图页仅取消 UI 回调，App 终止时再完整 shutdown 释放 PTP 与 Browser 资源。

Co-authored-by: Cursor <cursoragent@cursor.com>

suixinkanTests/CameraTethering/CameraServiceFactoryTests.swift

@@ -0,0 +1,34 @@
+//
+//  CameraServiceFactoryTests.swift
+//  suixinkanTests
+//
+
+import XCTest
+@testable import suixinkan
+
+/// CameraServiceFactory 测试。
+@MainActor
+final class CameraServiceFactoryTests: XCTestCase {
+    func testMakeSonyReturnsSonyService() {
+        let service = CameraServiceFactory.make(brand: .sony)
+        XCTAssertTrue(service is SonyCameraService)
+        XCTAssertEqual(service.brand, .sony)
+    }
+
+    func testMakeCanonReturnsCanonService() {
+        let service = CameraServiceFactory.make(brand: .canon)
+        XCTAssertTrue(service is CanonCameraService)
+        XCTAssertEqual(service.brand, .canon)
+    }
+
+    func testMakeAutoDetectReturnsAutoDetectService() {
+        let service = CameraServiceFactory.makeAutoDetect()
+        XCTAssertTrue(service is AutoDetectCameraService)
+    }
+
+    func testMakeAutoDetectReturnsSharedInstance() {
+        let first = CameraServiceFactory.makeAutoDetect()
+        let second = CameraServiceFactory.makeAutoDetect()
+        XCTAssertTrue(first === second)
+    }
+}