支持运行中切换目标流量：按 S 进入输入模式，回车生效、Esc 取消

- 输入模式下控制循环照常运行、原目标继续生效，直到回车确认新值
- 输入期间终端输出整体静默（状态行/性能报告均不打印），文件日志与 CSV 照常写入
- 新增 ConsoleGate 过滤器挂到 console_handler，退出路径统一解除静默
- 新增 PerformanceReporter.reset()，切换目标后重新判稳并再次输出性能报告
- 新增 config.TARGET_SWITCH_KEY 配置项，README 同步说明

main.py

@@ -13,6 +13,11 @@ from pathlib import Path
 import sys
 import time
 
+try:
+    import msvcrt  # Windows 专用：非阻塞键盘输入，用于运行中切换目标流量
+except ImportError:  # 非 Windows 平台无此模块，退化为仅周期控制
+    msvcrt = None
+
 import config
 from controllers import IncrementalPID
 from data_logger import FlowRunRecorder
@@ -20,6 +25,17 @@ from flow_control import FlowControlFault, FlowControlLoop
 from performance_reporter import PerformanceReporter
 
 
+class ConsoleGate(logging.Filter):
+    """终端输出闸门：输入模式下挡住终端日志，文件日志不受影响。"""
+
+    def __init__(self):
+        super().__init__()
+        self.blocked = False
+
+    def filter(self, _record):
+        return not self.blocked
+
+
 def build_logger():
     log_dir = Path(__file__).resolve().parent / config.LOG_DIRECTORY
     log_dir.mkdir(parents=True, exist_ok=True)
@@ -39,8 +55,10 @@ def build_logger():
 
     console_handler = logging.StreamHandler()
     console_handler.setFormatter(formatter)
+    console_gate = ConsoleGate()
+    console_handler.addFilter(console_gate)
     logger.addHandler(console_handler)
-    return logger
+    return logger, console_gate
 
 
 def build_control_loop(hardware, logger):
@@ -110,7 +128,7 @@ def format_status(result):
 
 def run(target_flow_slm):
     config.validate_config()
-    logger = build_logger()
+    logger, console_gate = build_logger()
     try:
         from PcControl import MT2AM8Client
     except ModuleNotFoundError as exc:
@@ -180,12 +198,79 @@ def run(target_flow_slm):
             plot_dpi=config.PLOT_DPI,
         )
         logger.info("逐周期数据将保存到 %s", recorder.csv_path)
-        logger.info("闭环控制已启动；按 Ctrl+C 停止")
+        logger.info(
+            "闭环控制已启动；按 Ctrl+C 停止，按 %s 切换目标流量",
+            config.TARGET_SWITCH_KEY.upper(),
+        )
+
+        input_mode = False
+        input_buf = ""
+
+        def apply_target():
+            """把输入缓冲区解析为新的目标流量并生效。"""
+            raw = input_buf.strip()
+            if not raw:
+                logger.warning("未输入目标流量，已忽略")
+                return
+            try:
+                value = float(raw)
+            except ValueError:
+                logger.warning("无法解析目标流量 %r，已忽略", raw)
+                return
+            try:
+                controller.set_target_flow(value)
+            except ValueError as exc:
+                logger.warning("目标流量设置失败：%s", exc)
+                return
+            reporter.reset()
+            logger.info("目标流量已切换为 %.3f SLM", value)
+
+        def process_keys():
+            """非阻塞处理键盘输入；输入模式下控制循环照常运行。"""
+            nonlocal input_mode, input_buf
+            if msvcrt is None:
+                return
+            while msvcrt.kbhit():
+                ch = msvcrt.getch()
+                if not input_mode:
+                    if ch == b"\x03":  # Ctrl+C，交给外层 KeyboardInterrupt 处理
+                        raise KeyboardInterrupt
+                    key = ch.decode("ascii", errors="ignore").lower()
+                    if key == config.TARGET_SWITCH_KEY:
+                        input_mode = True
+                        input_buf = ""
+                        console_gate.blocked = True
+                        print(
+                            f"当前目标={controller.target_flow_slm:.2f} SLM，"
+                            f"请输入新目标流量 (回车确认, Esc 取消): ",
+                            end="",
+                            flush=True,
+                        )
+                else:
+                    if ch in (b"\r", b"\n"):
+                        print()
+                        console_gate.blocked = False
+                        input_mode = False
+                        apply_target()
+                    elif ch == b"\x1b":  # Esc 取消
+                        console_gate.blocked = False
+                        input_mode = False
+                        print(" (已取消)")
+                    elif ch in (b"\x08", b"\x7f"):  # 退格删除最后一位
+                        if input_buf:
+                            input_buf = input_buf[:-1]
+                            print("\b \b", end="", flush=True)
+                    else:
+                        text = ch.decode("ascii", errors="ignore")
+                        if text and text.isprintable():
+                            input_buf += text
+                            print(text, end="", flush=True)
 
         next_deadline = time.perf_counter()
         next_status_time = next_deadline
         while True:
             now = time.perf_counter()
+            process_keys()
             result = controller.step(now=now)
             recorder.record(result)
             reporter.observe(result)
@@ -207,14 +292,18 @@ def run(target_flow_slm):
                 next_deadline = time.perf_counter()
 
     except KeyboardInterrupt:
+        console_gate.blocked = False
         logger.info("收到 Ctrl+C，正在停止控制")
     except FlowControlFault as exc:
+        console_gate.blocked = False
         exit_code = 2
         logger.critical("控制故障：%s", exc)
     except Exception:
+        console_gate.blocked = False
         exit_code = 3
         logger.exception("未处理异常，系统将退出")
     finally:
+        console_gate.blocked = False
         if connected:
             try:
                 hardware.disconnect()