feat(sdk): 帧间隔 frameIntervalMs 配置化（默认 35ms，[0,500] clamp）

DuooomiBleConfig 新增 frameIntervalMs，BleProtocolService 构造期注入。
顺手清死代码 FrameConstants.frameIntervalNanos、修 sendFrames 0.035 字面量
（统一走 config）。demo 加可调输入框 + UserDefaults 持久化。
越界 warn 不抛错，使用点 min/max 兜底。

设计稿：docs/superpowers/specs/2026-05-20-frame-interval-config-design.md

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

Sources/DuooomiBleSDK/Services/BleProtocolService.swift

@@ -10,6 +10,7 @@ final class BleProtocolService: BleClientDelegate {
 
     weak var delegate: BleProtocolServiceDelegate?
     private let client: BleClient
+    private let frameIntervalMs: Int
     private var isListening = false
 
     /// 分包重组会话
@@ -20,9 +21,10 @@ final class BleProtocolService: BleClientDelegate {
 
     private var fragments: [String: FragmentSession] = [:]
 
-    init(client: BleClient) {
+    init(client: BleClient, frameIntervalMs: Int) {
         self.client = client
-        BleLog.i("Protocol service created", "Protocol")
+        self.frameIntervalMs = frameIntervalMs
+        BleLog.i("Protocol service created (frameIntervalMs=\(frameIntervalMs))", "Protocol")
     }
 
     // MARK: - Start/Stop Listening
@@ -90,8 +92,9 @@ final class BleProtocolService: BleClientDelegate {
             onProgress?(Double(index + 1) / Double(total))
 
             if index + 1 < total {
-                // Inter-frame delay 35ms
-                DispatchQueue.global(qos: .userInitiated).asyncAfter(deadline: .now() + 0.035) {
+                // Inter-frame delay from config (clamped to [0,500]ms)
+                let delaySec = Double(min(max(self.frameIntervalMs, 0), 500)) / 1000.0
+                DispatchQueue.global(qos: .userInitiated).asyncAfter(deadline: .now() + delaySec) {
                     sendFrame(at: index + 1)
                 }
             } else {