新增输出稳态时滑动窗口流量均值和标准差，以及稳态误差（判稳成功时目标流量减去当时流量）。

目前逻辑是「一直控制 + 每秒状态照常输出 + 稳态时额外多打印一次性能报告」。
新增一个可选的自动停止功能--config开关，「达到稳态后自动停止控制」，让 reporter 通知主循环退出。

performance_reporter.py

@@ -43,6 +43,9 @@ class PerformanceReporter:
 
         self.target_flow_slm = None
         self.settling_time_s = None
+        self.steady_mean = None
+        self.steady_std = None
+        self.steady_error_slm = None
         self._first_timestamp = None
         self._peak_flow_slm = None
         self._min_flow_slm = None
@@ -94,6 +97,9 @@ class PerformanceReporter:
         if abs(mean - target) <= band and std <= std_threshold:
             self._reached = True
             self.settling_time_s = elapsed_s
+            self.steady_mean = mean
+            self.steady_std = std
+            self.steady_error_slm = target - mean
             self._report()
 
     def finalize(self):
@@ -101,6 +107,11 @@ class PerformanceReporter:
         if not self._reached and self.target_flow_slm is not None:
             self._log("info", "本次运行未达到稳态，未生成控制性能报告")
 
+    @property
+    def steady_reached(self):
+        """是否已判定达到稳态（供主循环决定是否自动停止）。"""
+        return self._reached
+
     def _report(self):
         target = self.target_flow_slm
         initial = self.initial_flow_slm
@@ -134,6 +145,12 @@ class PerformanceReporter:
                 f"{self.flow_range_max_slm:.3f} SLM"
             ),
             f"调节时间(至稳态): {self.settling_time_s:.3f} s",
+            f"稳态流量(窗口均值): {self.steady_mean:.3f} SLM",
+            f"稳态标准差(窗口): {self.steady_std:.3f} SLM",
+            (
+                f"稳态误差: {self.steady_error_slm:+.3f} SLM "
+                f"(目标 - 稳态均值)"
+            ),
             f"初始流量: {initial:.3f} SLM",
             (
                 f"超调量: {extremum_text}，{direction} "