demo app + SDK updates:\n- Add direct ANI transfer (prepare -> transfer)\n- Add firmware update flow (fetch latest w/ x-api-key, OTA transfer)\n- Extract x-api-key to NetworkConstants\n- Rename example app to demo; move folder and entry to DemoApp\n- Switch from SPM package dependency to local framework target\n- Enable automatic Info.plist generation for framework target\n- Add placeholder test to satisfy SwiftPM test target\n- Regenerate XcodeGen project (demo.xcodeproj)

Sources/DuooomiBleSDK/Protocol/ProtocolFrame.swift

@@ -0,0 +1,20 @@
+import Foundation
+
+/// BLE 协议帧结构
+/// 格式: [head:1][type:1][subpageTotal:2][curPage:2][dataLen:2][data:N][checksum:1]
+public struct ProtocolFrame: Sendable {
+    /// 传输方向标识 (0xC7 = APP→Device, 0xB0 = Device→APP)
+    public let head: UInt8
+    /// 命令类型，对应 CommandType
+    public let type: UInt8
+    /// 总分包数 (0 = 单帧不分包)
+    public let subpageTotal: UInt16
+    /// 当前包序号 (从 total-1 倒数到 0)
+    public let curPage: UInt16
+    /// 数据段字节长度
+    public let dataLen: UInt16
+    /// 数据段内容
+    public let data: Data
+    /// 校验字节
+    public let checksum: UInt8
+}