Add enemy foundation: definitions, components, ranged damage (#44)

Enemy.gd now resolves stats/hull/color from EnemyDefinition resources
and composes behaviour from capability components (EnemyPursuitComponent
holds today's chase-the-nearest-ship logic), the same shape Ship.gd
already uses for vessels. Fleet lookups go through a "player_fleet"
group instead of a hardcoded ../Fleet sibling path, so an enemy parented
anywhere (e.g. under a planet surface's SurfaceFeatures) still finds it.

Also closes a real gap: enemies previously had no way to damage the
fleet at range at all (Ship only reacted to physical contact,
Projectile.gd was player-only). Ship.take_damage() is now a proper
entry point - contact damage routes through it unchanged - and
EnemyProjectile lets an enemy component fire at player_ships. Both
ranged enemy archetypes in #45/#46 build on this.

Part of the #40 conquest-mechanic breakdown.

Enemy.gd

@@ -2,50 +2,53 @@ extends Area2D
 
 signal destroyed
 
-@export var speed: float = 140.0
-@export var acceleration: float = 260.0
-@export var rotation_speed: float = 6.0
-@export var max_hp: int = 3
+const ENEMY_DEFINITIONS = preload("res://EnemyDefinitions.gd")
 
-var velocity: Vector2 = Vector2.ZERO
+@export var enemy_id: String = "chaser"
+
+var definition: Resource
 var hp: int
 
-@onready var fleet: Node2D = get_node("../Fleet")
-
+# Mirrors Ship.gd's own max_speed/acceleration: copied from the definition
+# once, then mutable, so a test/preview can pin an enemy in place (e.g.
+# `enemy.speed = 0.0`) without needing to know about definitions at all.
+var speed: float
+var acceleration: float
+var rotation_speed: float
+var max_hp: int
 
 
 func _ready() -> void:
-	hp = max_hp
 	add_to_group("enemies")
+	definition = ENEMY_DEFINITIONS.get_definition(enemy_id)
+	speed = definition.speed
+	acceleration = definition.acceleration
+	rotation_speed = definition.rotation_speed
+	max_hp = definition.max_hp
+	hp = max_hp
+	for component_scene in definition.component_scenes:
+		var component: Node = component_scene.instantiate()
+		add_child(component)
+		if component.has_method("setup"):
+			component.setup()
 	queue_redraw()
 
 
+func get_component(capability: String) -> Node:
+	for child in get_children():
+		if child.get("capability_id") == capability:
+			return child
+	return null
+
+
+func has_capability(capability: String) -> bool:
+	return get_component(capability) != null
+
+
 func _physics_process(delta: float) -> void:
-	var target_pos: Vector2 = _nearest_ship_position()
-	var to_target: Vector2 = target_pos - position
-
-	if to_target.length() > 1.0:
-		var desired_velocity: Vector2 = to_target.normalized() * speed
-		velocity = velocity.move_toward(desired_velocity, acceleration * delta)
-		position += velocity * delta
-
-	if velocity.length() > 5.0:
-		var target_angle: float = velocity.angle() + PI / 2.0
-		rotation = lerp_angle(rotation, target_angle, rotation_speed * delta)
-
-
-func _nearest_ship_position() -> Vector2:
-	if fleet.ships.is_empty():
-		return position
-
-	var nearest: Node2D = fleet.ships[0]
-	var best_dist: float = position.distance_to(nearest.position)
-	for ship in fleet.ships:
-		var d: float = position.distance_to(ship.position)
-		if d < best_dist:
-			best_dist = d
-			nearest = ship
-	return nearest.position
+	for child in get_children():
+		if child.has_method("tick"):
+			child.tick(delta)
 
 
 func take_damage(amount: int) -> void:
@@ -57,8 +60,9 @@ func take_damage(amount: int) -> void:
 
 
 func _draw() -> void:
-	var points: PackedVector2Array = PackedVector2Array([
-		Vector2(0, -16), Vector2(12, 0), Vector2(0, 16), Vector2(-12, 0)
+	var points: PackedVector2Array = definition.hull_points if definition != null else PackedVector2Array([
+		Vector2(0, -16), Vector2(12, 0), Vector2(0, 16), Vector2(-12, 0),
 	])
+	var glow: Color = definition.glow_color if definition != null else Color(1.0, 0.15, 0.2)
 	# Constant glow - see Ship.gd. Nothing animates, so no per-frame redraw.
-	NeonDraw.draw_glowing_polygon(self, points, Color(1.0, 0.15, 0.2), 1.0)
+	NeonDraw.draw_glowing_polygon(self, points, glow, 1.0)