重构：模块化 RRPP Lite 并更新入口

lite/rrpp_core/traffic.py

@@ -0,0 +1,55 @@
+"""线程安全的本地转发流量统计。"""
+
+import threading
+import time
+
+
+class TrafficStats:
+    """记录单次代理会话的上下行总量与采样速率。"""
+
+    def __init__(self, clock=time.time):
+        self._clock = clock
+        self._lock = threading.Lock()
+        self._up = 0
+        self._down = 0
+        self._prev_up = 0
+        self._prev_down = 0
+        self._prev_ts = 0.0
+
+    def add(self, up=0, down=0):
+        with self._lock:
+            self._up += up
+            self._down += down
+
+    def reset(self):
+        with self._lock:
+            self._up = self._down = 0
+            self._prev_up = self._prev_down = 0
+            self._prev_ts = self._clock()
+
+    def rate(self):
+        with self._lock:
+            now = self._clock()
+            if self._prev_ts > 0 and now > self._prev_ts:
+                elapsed = now - self._prev_ts
+                up_rate = int((self._up - self._prev_up) / elapsed)
+                down_rate = int((self._down - self._prev_down) / elapsed)
+            else:
+                up_rate = down_rate = 0
+            self._prev_up = self._up
+            self._prev_down = self._down
+            self._prev_ts = now
+            return up_rate, down_rate, self._up, self._down
+
+    def snapshot(self):
+        with self._lock:
+            return self._up, self._down
+
+
+def format_bytes(value):
+    """将字节数格式化为 UI 展示文本。"""
+    number = float(value)
+    for unit in ("B", "KB", "MB", "GB", "TB"):
+        if number < 1024 or unit == "TB":
+            return f"{int(number)} {unit}" if unit == "B" else f"{number:.1f} {unit}"
+        number /= 1024