Add sound effects and character scripts

- Imported new sound effects: "Low Boing", "Low Whoosh", and "Pew" with corresponding import files.
- Created a new character script for "Hen" with basic AI and attack functionality.
- Implemented an effect controller script for managing particle effects with one-shot functionality.

resources/sounds/effect/Pew.mp3.import

@@ -0,0 +1,19 @@
+[remap]
+
+importer="mp3"
+type="AudioStreamMP3"
+uid="uid://b7pxuov1id0ho"
+path="res://.godot/imported/Pew.mp3-f95c3f433a0fb10603c74a8216172756.mp3str"
+
+[deps]
+
+source_file="res://resources/sounds/effect/Pew.mp3"
+dest_files=["res://.godot/imported/Pew.mp3-f95c3f433a0fb10603c74a8216172756.mp3str"]
+
+[params]
+
+loop=false
+loop_offset=0
+bpm=0
+beat_count=0
+bar_beats=4