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/DuooomiBleConfig.swift

@@ -6,8 +6,8 @@ public struct DuooomiBleConfig {
     public let apiHost: URL
     /// API 鉴权 key（Loomart x-api-key）
     public let apiKey: String
-    /// 多租户 owner 标识，所有 RPC 必带 `x-owner` header
-    public let owner: String
+    /// 设备品牌名（所有 RPC 必带 `x-owner` header）
+    public let brand: String
     /// CDN 资源地址（末尾带 `/`）
     public let cdnHost: String
     /// ANI 转换宽度（像素）
@@ -22,7 +22,7 @@ public struct DuooomiBleConfig {
     public init(
         apiHost: URL = URL(string: "https://api.duooomi.com")!,
         apiKey: String,
-        owner: String,
+        brand: String,
         cdnHost: String = "https://cdn.bowong.cc/",
         aniWidth: Int = 360,
         aniHeight: Int = 360,
@@ -31,7 +31,7 @@ public struct DuooomiBleConfig {
     ) {
         self.apiHost = apiHost
         self.apiKey = apiKey
-        self.owner = owner
+        self.brand = brand
         self.cdnHost = cdnHost.hasSuffix("/") ? cdnHost : cdnHost + "/"
         self.aniWidth = aniWidth
         self.aniHeight = aniHeight