fix: 调整游戏难度和平衡性

将初始波数从10改为1以降低游戏初始难度
减少猫角色的攻击冷却时间范围从3500-8000到2500-6000
添加背景图片资源文件

resources/maps/background.jpeg.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://bjnooofncaadd"
+path="res://.godot/imported/background.jpeg-f024d3395620fa6dca7f59dfebae682f.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://resources/maps/background.jpeg"
+dest_files=["res://.godot/imported/background.jpeg-f024d3395620fa6dca7f59dfebae682f.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1

scripts/Contents/Characters/Cat.gd

@@ -4,7 +4,7 @@ class_name Maodie
 func register():
 	fields[FieldStore.Entity.MAX_HEALTH] = 75
 	fields[FieldStore.Entity.MOVEMENT_SPEED] = randf_range(0.5, 0.8)
-	attackCooldownMap[0] = randi_range(3500, 8000)
+	attackCooldownMap[0] = randi_range(2500, 6000)
 	sprintMultiplier = randf_range(10, 35)
 func ai():
 	PresetEntityAI.follow(self, currentFocusedBoss)

scripts/Contents/Wave.gd

@@ -22,7 +22,7 @@ func duplicate() -> Wave:
 	wave.per = per
 	return wave
 
-static var current: int = startWith(10)
+static var current: int = startWith(1)
 static var WAVE_NORMAL = [
 	Wave.create("Hen", 1, 3, false, 0, INF, 1),
 	Wave.create("Cat", 1, 3, false, 0, INF, 1),