✨ feat(runtime): 添加轨迹持久化与密集执行链路

* 新增飞拍轨迹文件存储，支持上传、加载与删除
* 接通 ControllerClientCompat 到运行时的轨迹编排
* 完善 FANUC 命令与 J519 客户端发送链路
* 补充密集轨迹执行、运行时编排和协议客户端测试
* 更新 README 与 AGENTS 中的当前实现状态

tests/Flyshot.Core.Tests/FanucJ519ClientTests.cs

@@ -177,4 +177,43 @@ public sealed class FanucJ519ClientTests : IDisposable
         using var client = new FanucJ519Client();
         Assert.Throws<InvalidOperationException>(() => client.StartMotion());
     }
+
+    /// <summary>
+    /// 验证 Stopwatch + SpinWait 发送循环能保持约 8ms 周期抖动在亚毫秒级。
+    /// </summary>
+    [Fact]
+    public async Task StartMotion_MaintainsSubMillisecondPeriod()
+    {
+        using var client = new FanucJ519Client();
+        await client.ConnectAsync("127.0.0.1", Port, _cts.Token);
+        await _server.ReceiveAsync(_cts.Token); // init
+
+        var command = new FanucJ519Command(sequence: 1, targetJoints: [1.0, 2.0, 3.0, 4.0, 5.0, 6.0]);
+        client.UpdateCommand(command);
+        client.StartMotion();
+
+        // 收集 5 个命令包到达时间戳。
+        var timestamps = new List<DateTimeOffset>();
+        for (var i = 0; i < 5; i++)
+        {
+            var result = await _server.ReceiveAsync(_cts.Token);
+            timestamps.Add(DateTimeOffset.UtcNow);
+        }
+
+        await client.StopMotionAsync(_cts.Token);
+
+        // 计算相邻包间隔并断言最大抖动。
+        var intervals = new List<TimeSpan>();
+        for (var i = 1; i < timestamps.Count; i++)
+        {
+            intervals.Add(timestamps[i] - timestamps[i - 1]);
+        }
+
+        // 允许 ±2ms 的测量误差（含 UDP 传输和调度延迟）。
+        Assert.All(intervals, interval =>
+        {
+            Assert.True(interval >= TimeSpan.FromMilliseconds(6), $"间隔 {interval.TotalMilliseconds:F2}ms 过短。");
+            Assert.True(interval <= TimeSpan.FromMilliseconds(10), $"间隔 {interval.TotalMilliseconds:F2}ms 过长。");
+        });
+    }
 }