refactor(MathTool): 重命名随机数生成方法并优化蘑菇矿挖爪属性

将 randomVector2In 重命名为 sampleInCircle，randomRingPoint 重命名为 sampleInRing，randChoiceWeightsFrom 重命名为 randomChoiceFromWeights，signBeforeStr 重命名为 toSigned
调整蘑菇矿挖爪的攻击力和掉落率，减少基础伤害至0.5，固定掉落率为0.1，优化物品掉落逻辑

scripts/Contents/Weapons/MushroomPickaxe.gd

@@ -2,8 +2,8 @@
 extends Weapon
 
 func update(to: int, origin: Dictionary, _entity: EntityBase):
-	origin["atk"] += 1 * to * soulLevel
-	origin["rate"] += 0.04 * to * soulLevel
+	origin["atk"] += 0.5 * to * soulLevel
+	origin["rate"] = 0.1 * soulLevel
 	origin["count"] += 1 * to * soulLevel
 	return origin
 func attack(entity: EntityBase):