Add weighted_choice utility and improve easter_egg randomness

Introduced a weighted_choice function for weighted random selection. Refactored the easter_egg function to use weighted_choice for more flexible and controlled message selection, replacing the previous randint-based logic.

bot.py

@@ -15,7 +15,6 @@ import platform
 import traceback
 from pathlib import Path
 from rich.traceback import install
-from random import randint
 
 # maim_message imports for console input
 
@@ -25,6 +24,9 @@ initialize_logging()
 
 from src.main import MainSystem #noqa
 from src.manager.async_task_manager import async_task_manager #noqa
+from colorama import init, Fore
+import random
+from typing import List, Sequence, Optional
 
 
 
@@ -63,17 +65,48 @@ async def request_shutdown() -> bool:
         logger.error(f"请求关闭程序时发生错误: {e}")
         return False
 
+def weighted_choice(data: Sequence[str],
+                    weights: Optional[List[float]] = None) -> str:
+    """
+    从 data 中按权重随机返回一条。
+    若 weights 为 None，则所有元素权重默认为 1。
+    """
+    if weights is None:
+        weights = [1.0] * len(data)
+
+    if len(data) != len(weights):
+        raise ValueError("data 和 weights 长度必须相等")
+
+    # 计算累计权重区间
+    total = 0.0
+    acc = []
+    for w in weights:
+        total += w
+        acc.append(total)
+
+    if total <= 0:
+        raise ValueError("总权重必须大于 0")
+
+    # 随机落点
+    r = random.random() * total
+    # 二分查找落点所在的区间
+    left, right = 0, len(acc) - 1
+    while left < right:
+        mid = (left + right) // 2
+        if r < acc[mid]:
+            right = mid
+        else:
+            left = mid + 1
+    return data[left]
 
 def easter_egg():
     # 彩蛋
-    from colorama import init, Fore
-
     init()
-    a = randint(1,11)
+    items = ["多年以后，面对AI行刑队，张三将会回想起他2023年在会议上讨论人工智能的那个下午", 
-    if a<2:
+             "你知道吗？诺狐的耳朵很软，很好rua", 
-        text = "喵喵~你的麦麦被猫娘入侵了喵~"
+             "喵喵~你的麦麦被猫娘入侵了喵~"]
-    else:
+    w = [10, 5, 2]
-        text = "多年以后，面对AI行刑队，张三将会回想起他2023年在会议上讨论人工智能的那个下午"
+    text = weighted_choice(items, w)
     rainbow_colors = [Fore.RED, Fore.YELLOW, Fore.GREEN, Fore.CYAN, Fore.BLUE, Fore.MAGENTA]
     rainbow_text = ""
     for i, char in enumerate(text):