feat(sdk): 重命名 owner→brand 并在硬绑前校验设备品牌

- DuooomiBleConfig.owner → brand（语义：设备品牌名），HTTP header x-owner 不变
- bind() 前置 verifyBrand：缺 deviceInfo 先 getDeviceInfo，与 config.brand 严格匹配，不一致主动断连并抛 .brandMismatch
- README 抹除软绑/对账/UpgradeRecord 等内部实现细节，仅保留厂商面向的公开 API（功能代码完全保留）

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

demo/Sources/DemoApp.swift

@@ -20,8 +20,8 @@ final class DemoViewModel: NSObject, ObservableObject, DuooomiBleSDKDelegate {
 
     // MARK: - SDK Config（demo 内可改，持久化到 UserDefaults）
 
-    @Published var configOwner: String {
-        didSet { defaults.set(configOwner, forKey: Self.keyOwner) }
+    @Published var configBrand: String {
+        didSet { defaults.set(configBrand, forKey: Self.keyBrand) }
     }
     @Published var configApiKey: String {
         didSet { defaults.set(configApiKey, forKey: Self.keyApiKey) }
@@ -47,28 +47,28 @@ final class DemoViewModel: NSObject, ObservableObject, DuooomiBleSDKDelegate {
     // MARK: - Internals
 
     private let defaults = UserDefaults.standard
-    private static let keyOwner = "demo.config.owner"
+    private static let keyBrand = "demo.config.brand"
     private static let keyApiKey = "demo.config.apiKey"
     private static let keyScanPrefix = "demo.config.scanPrefix"
 
     /// demo 调试默认值（仅当 UserDefaults 没存过时使用）。秘钥从 DemoSecrets 读，避免泄露到仓库。
-    private static let defaultOwner = DemoSecrets.owner
+    private static let defaultBrand = DemoSecrets.brand
     private static let defaultApiKey = DemoSecrets.apiKey
     private static let defaultScanPrefix = DemoSecrets.scanNamePrefix
 
     override init() {
         let d = UserDefaults.standard
-        let owner = d.string(forKey: Self.keyOwner) ?? Self.defaultOwner
+        let brand = d.string(forKey: Self.keyBrand) ?? Self.defaultBrand
         let apiKey = d.string(forKey: Self.keyApiKey) ?? Self.defaultApiKey
         let scanPrefix = d.string(forKey: Self.keyScanPrefix) ?? Self.defaultScanPrefix
 
-        self.configOwner = owner
+        self.configBrand = brand
         self.configApiKey = apiKey
         self.configScanPrefix = scanPrefix
 
         self.sdk = DuooomiBleSDK(config: .init(
             apiKey: apiKey,
-            owner: owner,
+            brand: brand,
             scanNamePrefix: scanPrefix
         ))
 
@@ -82,7 +82,7 @@ final class DemoViewModel: NSObject, ObservableObject, DuooomiBleSDKDelegate {
     func reloadSDK() {
         let new = DuooomiBleSDK(config: .init(
             apiKey: configApiKey,
-            owner: configOwner,
+            brand: configBrand,
             scanNamePrefix: configScanPrefix
         ))
         new.delegate = self