feat(武器): 重做链式机枪并添加音效

重构链式机枪的子弹生成逻辑，降低散射衰减系数
添加射击音效资源及导入配置
调整武器属性描述和数值
移除测试用的调试代码

resources/sounds/effect/chainshoot.wav.import

@@ -0,0 +1,24 @@
+[remap]
+
+importer="wav"
+type="AudioStreamWAV"
+uid="uid://bdcyao3e6xs63"
+path="res://.godot/imported/chainshoot.wav-a0d7629f12757fe65a40d82f1ed87019.sample"
+
+[deps]
+
+source_file="res://resources/sounds/effect/chainshoot.wav"
+dest_files=["res://.godot/imported/chainshoot.wav-a0d7629f12757fe65a40d82f1ed87019.sample"]
+
+[params]
+
+force/8_bit=false
+force/mono=false
+force/max_rate=false
+force/max_rate_hz=44100
+edit/trim=false
+edit/normalize=false
+edit/loop_mode=0
+edit/loop_begin=0
+edit/loop_end=-1
+compress/mode=2