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/Spawnable_Objects/Projectiles_To_Load/melee_projectile.tscn

@@ -0,0 +1,14 @@
+[gd_scene load_steps=3 format=3 uid="uid://6rfh1ejt4m6m"]
+
+[ext_resource type="Script" uid="uid://bfn8eu00l4btq" path="res://client/template/scripts/Projectiles/melee_weapon_projectile.gd" id="1_qlmbe"]
+
+[sub_resource type="BoxShape3D" id="BoxShape3D_q86ac"]
+
+[node name="MeleeProjectile" type="Node3D"]
+script = ExtResource("1_qlmbe")
+Projectile_Type = "over_ride"
+
+[node name="MeleeHitbox" type="ShapeCast3D" parent="."]
+shape = SubResource("BoxShape3D_q86ac")
+target_position = Vector3(0, 0, -1)
+collision_mask = 37