feat: 重写 SDK 支持 iOS 12.2，移除 async/await 和 Combine

- 所有公开 API 改为 completion handler (Result<T, Error>)
- 状态通知改为 DuooomiBleSDKDelegate 协议
- 移除 Sendable、@MainActor、AsyncStream、CheckedContinuation
- 网络请求改为 URLSession.dataTask 回调
- BLE 通信改为 delegate + 闭包模式
- deployment target 降至 iOS 12.2

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

demo/Sources/WrapperTestView.swift

@@ -21,18 +21,9 @@ private enum CDNHelper {
 }
 
 // MARK: - View
-//
-// Demo 演示 SDK 全部功能：
-// 1. Scan & Connect — sdk.scan() / sdk.connect(deviceId:) / sdk.disconnect()
-// 2. Device — sdk.getDeviceInfo() / sdk.getVersion() / sdk.bind(userId:) / sdk.unbind(userId:)
-// 3. Transfer — sdk.transferMedia(fileUrl:) 一步传输（内部自动 ANI 转换 + prepare + transfer）
-// 4. Firmware — sdk.fetchLatestFirmware() 查询 + sdk.transferFile(fileUri:commandType:.otaPackage) OTA
-// 5. Device Files — sdk.deleteFile(key:) 删除设备文件
-//
-// 可观察状态：btState / connectedDevice / deviceInfo / version / transferProgress / error
 
 struct WrapperTestView: View {
-    @EnvironmentObject var sdk: DuooomiBleSDK
+    @ObservedObject var viewModel: DemoViewModel
 
     @State private var userId = "test-user-001"
     @State private var fileUrl = "https://cdn.bowong.cc/material/569f48a8e29f47859b3a9808be37f94c.mp4"
@@ -68,9 +59,9 @@ struct WrapperTestView: View {
         .navigationTitle("SDK Demo")
         .scrollDismissesKeyboard(.interactively)
         .onAppear {
-            CDNHelper.cdnHost = sdk.config.cdnHost
-            firmwareBrand = sdk.config.firmwareIdentifier
-            firmwareStatus = sdk.config.firmwareStatus
+            CDNHelper.cdnHost = viewModel.sdk.config.cdnHost
+            firmwareBrand = viewModel.sdk.config.firmwareIdentifier
+            firmwareStatus = viewModel.sdk.config.firmwareStatus
         }
     }
 
@@ -78,15 +69,15 @@ struct WrapperTestView: View {
 
     private var statusSection: some View {
         Section("Status") {
-            LabeledContent("BLE", value: sdk.btState.rawValue)
-            LabeledContent("Device", value: sdk.connectedDevice?.name ?? "—")
-            LabeledContent("Version", value: sdk.version.isEmpty ? "—" : sdk.version)
-            if sdk.transferProgress > 0 {
-                ProgressView(value: Double(sdk.transferProgress), total: 100) {
-                    Text("\(sdk.transferProgress)%").font(.caption)
+            LabeledContent("BLE", value: viewModel.btState.rawValue)
+            LabeledContent("Device", value: viewModel.connectedDevice?.name ?? "—")
+            LabeledContent("Version", value: viewModel.version.isEmpty ? "—" : viewModel.version)
+            if viewModel.transferProgress > 0 {
+                ProgressView(value: Double(viewModel.transferProgress), total: 100) {
+                    Text("\(viewModel.transferProgress)%").font(.caption)
                 }
             }
-            if let err = sdk.error {
+            if let err = viewModel.error {
                 Text(err).foregroundStyle(.red).font(.caption)
             }
         }
@@ -96,19 +87,19 @@ struct WrapperTestView: View {
         Section("Scan & Connect") {
             HStack {
                 Button("Scan") {
-                    sdk.scan()
+                    viewModel.sdk.scan()
                     log("→ scan()")
                 }
                 .buttonStyle(.borderedProminent)
 
                 Button("Stop") {
-                    sdk.stopScan()
+                    viewModel.sdk.stopScan()
                     log("→ stopScan()")
                 }
                 .buttonStyle(.bordered)
             }
 
-            ForEach(sdk.discoveredDevices) { device in
+            ForEach(viewModel.discoveredDevices) { device in
                 HStack {
                     VStack(alignment: .leading) {
                         Text(device.name ?? "Unknown")
@@ -117,9 +108,9 @@ struct WrapperTestView: View {
                     Spacer()
                     Text("\(device.rssi) dBm").font(.caption).foregroundStyle(.secondary)
 
-                    if sdk.connectedDevice?.id == device.id {
+                    if viewModel.connectedDevice?.id == device.id {
                         Button("Disconnect") {
-                            Task { await runDisconnect() }
+                            runDisconnect()
                         }
                         .buttonStyle(.bordered)
                         .controlSize(.small)
@@ -128,7 +119,7 @@ struct WrapperTestView: View {
                         ProgressView().controlSize(.small)
                     } else {
                         Button("Connect") {
-                            Task { await runConnect(deviceId: device.id) }
+                            runConnect(deviceId: device.id)
                         }
                         .buttonStyle(.bordered)
                         .controlSize(.small)
@@ -141,23 +132,23 @@ struct WrapperTestView: View {
 
     private var deviceSection: some View {
         Section("Device") {
-            LabeledContent("Brand", value: sdk.deviceInfo?.brand ?? "—")
-            LabeledContent("Size", value: sdk.deviceInfo?.size ?? "—")
-            LabeledContent("Power", value: sdk.deviceInfo.map { "\($0.powerlevel)%" } ?? "—")
-            LabeledContent("Storage", value: sdk.deviceInfo.map { "\($0.freespace)/\($0.allspace)" } ?? "—")
+            LabeledContent("Brand", value: viewModel.deviceInfo?.brand ?? "—")
+            LabeledContent("Size", value: viewModel.deviceInfo?.size ?? "—")
+            LabeledContent("Power", value: viewModel.deviceInfo.map { "\($0.powerlevel)%" } ?? "—")
+            LabeledContent("Storage", value: viewModel.deviceInfo.map { "\($0.freespace)/\($0.allspace)" } ?? "—")
 
             HStack {
-                Button("getDeviceInfo") { Task { await runGetDeviceInfo() } }
-                Button("getVersion") { Task { await runGetVersion() } }
+                Button("getDeviceInfo") { runGetDeviceInfo() }
+                Button("getVersion") { runGetVersion() }
             }
             .buttonStyle(.bordered)
 
             HStack {
                 TextField("userId", text: $userId)
                     .textFieldStyle(.roundedBorder)
-                Button("bind") { Task { await runBind() } }
+                Button("bind") { runBind() }
                     .buttonStyle(.bordered)
-                Button("unbind") { Task { await runUnbind() } }
+                Button("unbind") { runUnbind() }
                     .buttonStyle(.bordered)
             }
         }
@@ -171,10 +162,10 @@ struct WrapperTestView: View {
                 .disableAutocorrection(true)
 
             Button("Transfer") {
-                Task { await runTransfer() }
+                runTransfer()
             }
             .buttonStyle(.borderedProminent)
-            .disabled(fileUrl.isEmpty || sdk.connectedDevice == nil || isBusy)
+            .disabled(fileUrl.isEmpty || viewModel.connectedDevice == nil || isBusy)
         }
     }
 
@@ -182,7 +173,7 @@ struct WrapperTestView: View {
 
     private var firmwareSection: some View {
         Section("Firmware Update") {
-            LabeledContent("Current Version", value: sdk.version.isEmpty ? "—" : sdk.version)
+            LabeledContent("Current Version", value: viewModel.version.isEmpty ? "—" : viewModel.version)
 
             HStack {
                 Text("Identifier")
@@ -200,7 +191,7 @@ struct WrapperTestView: View {
             if let info = firmwareInfo {
                 VStack(alignment: .leading, spacing: 6) {
                     LabeledContent("Latest", value: info.version)
-                    LabeledContent("Has Update", value: sdk.hasNewerFirmware(deviceVersion: sdk.version, serverVersion: info.version) ? "Yes" : "No")
+                    LabeledContent("Has Update", value: viewModel.sdk.hasNewerFirmware(deviceVersion: viewModel.version, serverVersion: info.version) ? "Yes" : "No")
                     if let size = info.fileSize {
                         let bytes = Int(size) ?? 0
                         LabeledContent("Size", value: ByteCountFormatter.string(fromByteCount: Int64(bytes), countStyle: .file))
@@ -228,16 +219,16 @@ struct WrapperTestView: View {
 
             HStack {
                 Button("Get Update Info") {
-                    Task { await runFetchFirmwareInfo() }
+                    runFetchFirmwareInfo()
                 }
                 .buttonStyle(.bordered)
                 .disabled(firmwareLoading || firmwareBrand.isEmpty)
 
                 Button("Upgrade") {
-                    Task { await runUpgradeFirmware() }
+                    runUpgradeFirmware()
                 }
                 .buttonStyle(.borderedProminent)
-                .disabled(firmwareInfo?.fileUrl.isEmpty != false || sdk.connectedDevice == nil || isBusy || firmwareLoading)
+                .disabled(firmwareInfo?.fileUrl.isEmpty != false || viewModel.connectedDevice == nil || isBusy || firmwareLoading)
             }
         }
     }
@@ -278,7 +269,7 @@ struct WrapperTestView: View {
                     Spacer()
 
                     Button(role: .destructive) {
-                        Task { await runDeleteFile(rawKey) }
+                        runDeleteFile(rawKey)
                     } label: {
                         Image(systemName: "trash")
                     }
@@ -306,117 +297,139 @@ struct WrapperTestView: View {
         if logs.count > 200 { logs.removeLast() }
     }
 
-    // MARK: - Actions
-    // 每个 run* 方法对应一个 SDK API 调用，展示输入/输出和错误处理
+    // MARK: - Actions (callback-based)
 
-    /// sdk.connect(deviceId:) → DiscoveredDevice
-    private func runConnect(deviceId: String) async {
+    private func runConnect(deviceId: String) {
         connectingDeviceId = deviceId
-        defer { connectingDeviceId = nil }
         log("→ connect(\(deviceId))")
-        do {
-            let device = try await sdk.connect(deviceId: deviceId)
-            log("connect ✓ \(device.name ?? device.id)", level: .success)
-        } catch {
-            log("connect ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.connect(deviceId: deviceId) { [self] result in
+            DispatchQueue.main.async {
+                self.connectingDeviceId = nil
+                switch result {
+                case .success(let device):
+                    self.log("connect ✓ \(device.name ?? device.id)", level: .success)
+                case .failure(let error):
+                    self.log("connect ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 
-    /// sdk.disconnect()
-    private func runDisconnect() async {
+    private func runDisconnect() {
         log("→ disconnect")
-        do {
-            try await sdk.disconnect()
-            deviceFiles = []
-            log("disconnect ✓", level: .success)
-        } catch {
-            log("disconnect ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.disconnect { [self] result in
+            DispatchQueue.main.async {
+                switch result {
+                case .success:
+                    self.deviceFiles = []
+                    self.log("disconnect ✓", level: .success)
+                case .failure(let error):
+                    self.log("disconnect ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 
-    /// sdk.getDeviceInfo() → DeviceInfo
-    private func runGetDeviceInfo() async {
+    private func runGetDeviceInfo() {
         isBusy = true
-        defer { isBusy = false }
         log("→ getDeviceInfo")
-        do {
-            let info = try await sdk.getDeviceInfo()
-            log("getDeviceInfo ✓ brand=\(info.brand) power=\(info.powerlevel)%", level: .success)
-        } catch {
-            log("getDeviceInfo ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.getDeviceInfo { [self] result in
+            DispatchQueue.main.async {
+                self.isBusy = false
+                switch result {
+                case .success(let info):
+                    self.log("getDeviceInfo ✓ brand=\(info.brand) power=\(info.powerlevel)%", level: .success)
+                case .failure(let error):
+                    self.log("getDeviceInfo ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 
-    /// sdk.getVersion() → VersionInfo
-    private func runGetVersion() async {
+    private func runGetVersion() {
         isBusy = true
-        defer { isBusy = false }
         log("→ getVersion")
-        do {
-            let info = try await sdk.getVersion()
-            log("getVersion ✓ \(info.version)", level: .success)
-        } catch {
-            log("getVersion ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.getVersion { [self] result in
+            DispatchQueue.main.async {
+                self.isBusy = false
+                switch result {
+                case .success(let info):
+                    self.log("getVersion ✓ \(info.version)", level: .success)
+                case .failure(let error):
+                    self.log("getVersion ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 
-    /// sdk.bind(userId:) → BindingResponse (sn + contents)。绑定后才能查看设备文件
-    private func runBind() async {
+    private func runBind() {
         isBusy = true
-        defer { isBusy = false }
         log("→ bind(\(userId))")
-        do {
-            let result = try await sdk.bind(userId: userId)
-            log("bind ✓ sn=\(result.sn) contents=\(result.contents.count)", level: .success)
-            deviceFiles = result.contents
-        } catch {
-            log("bind ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.bind(userId: userId) { [self] result in
+            DispatchQueue.main.async {
+                self.isBusy = false
+                switch result {
+                case .success(let resp):
+                    self.log("bind ✓ sn=\(resp.sn) contents=\(resp.contents.count)", level: .success)
+                    self.deviceFiles = resp.contents
+                case .failure(let error):
+                    self.log("bind ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 
-    /// sdk.unbind(userId:) → UnbindResponse。解绑后该账号的设备文件将被删除
-    private func runUnbind() async {
+    private func runUnbind() {
         isBusy = true
-        defer { isBusy = false }
         log("→ unbind(\(userId))")
-        do {
-            _ = try await sdk.unbind(userId: userId)
-            deviceFiles = []
-            log("unbind ✓", level: .success)
-        } catch {
-            log("unbind ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.unbind(userId: userId) { [self] result in
+            DispatchQueue.main.async {
+                self.isBusy = false
+                switch result {
+                case .success:
+                    self.deviceFiles = []
+                    self.log("unbind ✓", level: .success)
+                case .failure(let error):
+                    self.log("unbind ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 
-    /// sdk.transferMedia(fileUrl:) — 一步完成：自动转换 ANI + prepare + transfer
-    private func runTransfer() async {
+    private func runTransfer() {
         isBusy = true
-        defer { isBusy = false }
         log("→ transferMedia(\(fileUrl))")
-        do {
-            try await sdk.transferMedia(fileUrl: fileUrl)
-            log("transfer ✓", level: .success)
-        } catch {
-            log("transfer ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.transferMedia(fileUrl: fileUrl) { [self] result in
+            DispatchQueue.main.async {
+                self.isBusy = false
+                switch result {
+                case .success:
+                    self.log("transfer ✓", level: .success)
+                case .failure(let error):
+                    self.log("transfer ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 
-    /// sdk.deleteFile(key:) → DeleteFileResponse
-    private func runDeleteFile(_ rawKey: String) async {
+    private func runDeleteFile(_ rawKey: String) {
         isBusy = true
-        defer { isBusy = false }
         log("→ deleteFile(\(rawKey))")
-        do {
-            _ = try await sdk.deleteFile(key: rawKey)
-            log("deleteFile ✓", level: .success)
-            deviceFiles.removeAll { $0 == rawKey }
-        } catch {
-            log("deleteFile ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.deleteFile(key: rawKey) { [self] result in
+            DispatchQueue.main.async {
+                self.isBusy = false
+                switch result {
+                case .success:
+                    self.log("deleteFile ✓", level: .success)
+                    self.deviceFiles.removeAll { $0 == rawKey }
+                case .failure(let error):
+                    self.log("deleteFile ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 
-    /// sdk.fetchLatestFirmware(identifier:status:) → FirmwareInfo?
-    private func runFetchFirmwareInfo() async {
+    private func runFetchFirmwareInfo() {
         let brand = firmwareBrand.trimmingCharacters(in: .whitespacesAndNewlines)
         guard !brand.isEmpty else {
             firmwareError = "No identifier specified"
@@ -424,34 +437,41 @@ struct WrapperTestView: View {
         }
         firmwareLoading = true
         firmwareError = nil
-        defer { firmwareLoading = false }
         log("→ fetchLatestFirmware(\(brand), \(firmwareStatus))")
-        do {
-            let info = try await sdk.fetchLatestFirmware(identifier: brand, status: firmwareStatus)
-            firmwareInfo = info
-            if let info {
-                let hasUpdate = sdk.hasNewerFirmware(deviceVersion: sdk.version, serverVersion: info.version)
-                log("firmware latest: \(info.version), hasUpdate=\(hasUpdate)", level: .success)
-            } else {
-                log("no firmware available", level: .info)
+        viewModel.sdk.fetchLatestFirmware(identifier: brand, status: firmwareStatus) { [self] result in
+            DispatchQueue.main.async {
+                self.firmwareLoading = false
+                switch result {
+                case .success(let info):
+                    self.firmwareInfo = info
+                    if let info = info {
+                        let hasUpdate = self.viewModel.sdk.hasNewerFirmware(deviceVersion: self.viewModel.version, serverVersion: info.version)
+                        self.log("firmware latest: \(info.version), hasUpdate=\(hasUpdate)", level: .success)
+                    } else {
+                        self.log("no firmware available", level: .info)
+                    }
+                case .failure(let error):
+                    self.firmwareError = error.localizedDescription
+                    self.log("firmware info ✗ \(error.localizedDescription)", level: .error)
+                }
             }
-        } catch {
-            firmwareError = error.localizedDescription
-            log("firmware info ✗ \(error.localizedDescription)", level: .error)
         }
     }
 
-    /// 固件升级第二步：sdk.upgradeFirmware(fileUrl:)
-    private func runUpgradeFirmware() async {
+    private func runUpgradeFirmware() {
         guard let info = firmwareInfo, !info.fileUrl.isEmpty else { return }
         isBusy = true
-        defer { isBusy = false }
         log("→ upgradeFirmware \(info.version)")
-        do {
-            try await sdk.upgradeFirmware(fileUrl: info.fileUrl)
-            log("OTA ✓", level: .success)
-        } catch {
-            log("OTA ✗ \(error.localizedDescription)", level: .error)
+        viewModel.sdk.upgradeFirmware(fileUrl: info.fileUrl) { [self] result in
+            DispatchQueue.main.async {
+                self.isBusy = false
+                switch result {
+                case .success:
+                    self.log("OTA ✓", level: .success)
+                case .failure(let error):
+                    self.log("OTA ✗ \(error.localizedDescription)", level: .error)
+                }
+            }
         }
     }
 }