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>

Sources/DuooomiBleSDK/DuooomiBleSDK+Binding.swift

@@ -22,6 +22,48 @@ extension DuooomiBleSDK {
     /// - Note: `bind` / `unbind` / `setPlayMode` 共享 `0x0F` / `0x12` opId 通道，**不能并发**。
     public func bind(userId: String, completion: @escaping (Result<BindingResponse, Error>) -> Void) {
         guard ensureConnected(completion: completion) else { return }
+        verifyBrand { [weak self] result in
+            guard let self = self else { return }
+            switch result {
+            case .failure(let err):
+                completion(.failure(err))
+            case .success:
+                self.performHardBind(userId: userId, completion: completion)
+            }
+        }
+    }
+
+    /// 校验设备 brand 与 SDK 配置 brand 是否一致；缺失则先拉一次 deviceInfo。
+    /// 不一致时主动断连并回调 `.brandMismatch`。
+    private func verifyBrand(completion: @escaping (Result<Void, Error>) -> Void) {
+        if let cached = deviceInfo {
+            checkBrand(actual: cached.brand, completion: completion)
+            return
+        }
+        getDeviceInfo { [weak self] result in
+            guard let self = self else { return }
+            switch result {
+            case .failure(let err):
+                completion(.failure(err))
+            case .success(let info):
+                self.checkBrand(actual: info.brand, completion: completion)
+            }
+        }
+    }
+
+    private func checkBrand(actual: String, completion: @escaping (Result<Void, Error>) -> Void) {
+        let expected = config.brand
+        if actual == expected {
+            completion(.success(()))
+            return
+        }
+        BleLog.w("Brand mismatch: expected=\(expected), actual=\(actual); disconnecting", "Command")
+        disconnect { _ in
+            completion(.failure(DuooomiBleError.brandMismatch(expected: expected, actual: actual)))
+        }
+    }
+
+    private func performHardBind(userId: String, completion: @escaping (Result<BindingResponse, Error>) -> Void) {
         BleLog.d("Sending bind (userId=\(userId))", "Command")
 
         sendAsyncAndWait(commandType: .bindDevice, completion: { [weak self] result in