feat: Enhance game mechanics and structure

- Added `ColorBar` class for visual representation of values.
- Expanded `EntityBase` with new properties: `isBoss` and `weapons`, and implemented damage handling and entity generation methods.
- Updated `EntityStateBar` to use `ColorBar` for health representation.
- Introduced `BulletBase` scene and script for bullet mechanics, including damage handling and generation.
- Created `WorldTool` for managing the game world and root node.
- Implemented `EntityTool` for retrieving entities from hurtboxes.
- Added `GameRule` for managing game rules like friendly fire.
- Updated scene files to reflect new structures and added necessary resources.

scripts/Statemachine/BulletBase.gd

@@ -0,0 +1,33 @@
+extends Area2D
+class_name BulletBase
+
+@export var speed: float = 1
+@export var damage: float = 10
+
+var launcher: EntityBase = null
+
+func _ready():
+	area_entered.connect(hit)
+
+func hit(target: Node):
+	var entity: EntityBase = EntityTool.fromHurtbox(target)
+	if !entity || !launcher: return
+	if entity == launcher: return
+	if GameRule.allowFriendlyFire:
+		if entity.isPlayer() == launcher.isPlayer(): return
+	entity.takeDamage(self)
+
+static func generate(
+		bullet: PackedScene,
+	 	launchBy: EntityBase,
+	  	spawnPosition: Vector2,
+	  	spawnRotation: float,
+	   	addToWorld: bool = true
+	):
+	var instance: BulletBase = bullet.instantiate()
+	instance.launcher = launchBy
+	instance.position = spawnPosition
+	instance.rotation = spawnRotation
+	if addToWorld:
+		WorldTool.rootNode.add_child(instance)
+	return instance