feat: integrate ChaffGames FPS template as local player controller

Replaces the overhead box-mesh view with a full FPS character:

- mouse look, WASD movement, jump (Space), crouch (C), sprint (Shift), lean (Q/E)

- 6 weapons (LMB shoot, R reload, scroll switch, F melee, G drop)

- Crosshair HUD, ammo counter, sprint bar

- Client sends position to server at 20Hz for multiplayer visibility

- Server broadcasts positions to all peers

- Remote players shown as boxes (placeholder)

source: https://godotengine.org/asset-library/asset/2652 (MIT license)

client/template/scripts/Projectiles/rocket_launcher_projectile.gd

@@ -0,0 +1,23 @@
+extends Projectile
+
+@export var explosion: ShapeCast3D
+
+func _on_body_entered(_body, _proj, _norm):
+	var collision_location: Vector3 = _proj.global_position
+	explosion.global_position = collision_location
+	
+	explosion.force_shapecast_update()
+	var targets = explosion.get_collision_count()
+	
+	for t in targets:
+		var damage_target = explosion.get_collider(t)
+		var collision_point: Vector3 = explosion.get_collision_point(t)
+		var collision_normal: Vector3 = explosion.get_collision_normal(t)
+		var hit_scan_array = [damage_target,collision_point,collision_normal]
+		Hit_Scan_Collision(hit_scan_array,damage,collision_location)
+	
+	_proj.queue_free()
+	Projectiles_Spawned.erase(_proj)
+
+	if Projectiles_Spawned.is_empty():
+		queue_free()