feat(sdk): OTA 升级流程对齐 expo + 拆 extension 文件分层 + 秘钥本地化

主要改动：
- 新增 fetchLatestFirmware/upgradeFirmware/tryReportPendingUpgrade
  三段 OTA 接口，对齐 expo bindDeviceWithOrchestration 行为
- bind 仅做硬绑+getVersion，软绑/对账上报/拉最新固件搬到
  fetchLatestFirmware 内部串；软绑失败自动硬解回滚
- UpgradeRecord 复合主键 (sn, firmwareId) 持久化 + sn 级 in-flight 互斥
- DuooomiBleSDKDelegate 新增 didUpdateUpgradeRecords，集成方
  可观察对账上报结果（reported/outcome 状态）
- DuooomiBleSDK 主类按职责拆 5 个 extension 文件，公开 API 不变
- TargetFirmware 简化为只取必要字段 + 新增 forceUpgrade
- scanNamePrefix 改为必填 String
- demo 秘钥移至本地 DemoSecrets.swift (gitignored)
- README 重写：完整 OTA 流程示例 + 上报状态判定表

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

Sources/DuooomiBleSDK/DuooomiBleConfig.swift

@@ -4,38 +4,38 @@ import Foundation
 public struct DuooomiBleConfig {
     /// API 服务地址
     public let apiHost: URL
-    /// API 鉴权 key
+    /// 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
     /// CDN 资源地址（末尾带 `/`）
     public let cdnHost: String
-    /// 固件查询标识，如 "duomi"
-    public let firmwareIdentifier: String
-    /// 固件查询状态，如 "DRAFT" / "PUBLISHED"
-    public let firmwareStatus: String
     /// ANI 转换宽度（像素）
     public let aniWidth: Int
     /// ANI 转换高度（像素）
     public let aniHeight: Int
     /// ANI 转换帧率
     public let aniFps: String
+    /// 扫描时按设备蓝牙广播名前缀过滤（大小写不敏感）。**必填**，由集成方约定固件广播名前缀。
+    public let scanNamePrefix: String
 
     public init(
         apiHost: URL = URL(string: "https://api.duooomi.com")!,
         apiKey: String,
+        owner: String,
         cdnHost: String = "https://cdn.bowong.cc/",
-        firmwareIdentifier: String = "duomi",
-        firmwareStatus: String = "DRAFT",
         aniWidth: Int = 360,
         aniHeight: Int = 360,
-        aniFps: String = "24"
+        aniFps: String = "24",
+        scanNamePrefix: String
     ) {
         self.apiHost = apiHost
         self.apiKey = apiKey
+        self.owner = owner
         self.cdnHost = cdnHost.hasSuffix("/") ? cdnHost : cdnHost + "/"
-        self.firmwareIdentifier = firmwareIdentifier
-        self.firmwareStatus = firmwareStatus
         self.aniWidth = aniWidth
         self.aniHeight = aniHeight
         self.aniFps = aniFps
+        self.scanNamePrefix = scanNamePrefix
     }
 }