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.

EnemyProjectile.gd

@@ -0,0 +1,45 @@
+extends Area2D
+
+# Mirrors Projectile.gd, but travels the other direction: fired by an enemy
+# component (see EnemyRangedWeaponComponent, #45) and damages player_ships.
+# This is the half of ranged combat that never existed before #44 - enemies
+# could previously only hurt the fleet by physical contact.
+
+@export var speed: float = 260.0
+@export var lifetime: float = 3.0
+@export var damage: int = 1
+@export var bolt_length: float = 20.0
+@export var color: Color = Color(1.0, 0.4, 0.35)
+
+var velocity: Vector2 = Vector2.ZERO
+var age: float = 0.0
+
+
+func _ready() -> void:
+	add_to_group("enemy_projectiles")
+	area_entered.connect(_on_area_entered)
+	queue_redraw()
+
+
+func launch(direction: Vector2) -> void:
+	velocity = direction.normalized() * speed
+	rotation = direction.angle() + PI / 2.0
+
+
+func _physics_process(delta: float) -> void:
+	position += velocity * delta
+	age += delta
+	if age >= lifetime:
+		queue_free()
+
+
+func _on_area_entered(area: Area2D) -> void:
+	if area.is_in_group("player_ships"):
+		area.take_damage(damage)
+		queue_free()
+
+
+func _draw() -> void:
+	var tip: Vector2 = Vector2(0, -bolt_length * 0.6)
+	var tail: Vector2 = Vector2(0, bolt_length * 0.4)
+	NeonDraw.draw_glowing_line(self, tail, tip, color, 1.0, 0.5)