Integrate Kenney Starter Kit FPS assets + comprehensive test suite

Assets (CC0 license):
- 3D models: Blaster gun, walls, platforms, grass, clouds, enemy
- Sounds: blaster fire, impacts, footsteps, jumps, weapon change
- Sprites: crosshair, hit marker, muzzle flash, skybox, blob shadow
- Font: Lilita One

Code changes:
- weapon_manager.gd: load blaster.glb as gun model (replaces box mesh)
- player.tscn: use Kenney sounds (blaster.ogg, enemy_hurt/destroy) and crosshair

Test suite (100 unit tests + 4 integration scenarios):
- weapon_data.gd: 27 tests — all 6 weapons every stat verified
- economy.gd: 19 tests — constants, loss streak, buy thresholds
- bomb.gd: 15 tests — state machine, timing constants
- round_manager.gd: 10 tests — win conditions, elimination logic
- team_manager.gd: 8 tests — auto-balance, team assignment
- headless_test_bot.gd: integration bot with movement/idle/rounds scenarios
- run_multi_bot.sh: multi-client launcher

assets/kenney-fps/scripts/audio.gd

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+extends Node
+
+# Code adapted from KidsCanCode
+
+var num_players = 12
+var bus = "master"
+
+var available = []  # The available players.
+var queue = []  # The queue of sounds to play.
+
+func _ready():
+	for i in num_players:
+		var p = AudioStreamPlayer.new()
+		add_child(p)
+
+		available.append(p)
+
+		p.volume_db = -10
+		p.finished.connect(_on_stream_finished.bind(p))
+		p.bus = bus
+
+func _on_stream_finished(stream):
+	available.append(stream)
+
+func play(sound_path):  # Path (or multiple, separated by commas)
+	var sounds = sound_path.split(",")
+	queue.append("res://" + sounds[randi() % sounds.size()].strip_edges())
+
+func _process(_delta):
+	if not queue.is_empty() and not available.is_empty():
+		available[0].stream = load(queue.pop_front())
+		available[0].play()
+		available[0].pitch_scale = randf_range(0.9, 1.1)
+
+		available.pop_front()

assets/kenney-fps/scripts/audio.gd.uid

@@ -0,0 +1 @@
+uid://d2fg3ewfjx4u4

assets/kenney-fps/scripts/hud.gd

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+extends CanvasLayer
+
+
+func _on_health_updated(health):
+	$Health.text = str(health) + "%"

assets/kenney-fps/scripts/hud.gd.uid

@@ -0,0 +1 @@
+uid://by0qn28x1i1jj

assets/kenney-fps/scripts/weapon.gd

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+extends Resource
+class_name Weapon
+
+@export_subgroup("Model")
+@export var model: PackedScene # Model of the weapon
+@export var position: Vector3 # On-screen position
+@export var rotation: Vector3 # On-screen rotation
+@export var muzzle_position: Vector3 # On-screen position of muzzle flash
+
+@export_subgroup("Properties")
+@export_range(0.1, 1) var cooldown: float = 0.1 # Firerate
+@export_range(1, 20) var max_distance: int = 10 # Fire distance
+@export_range(0, 100) var damage: float = 25 # Damage per hit
+@export_range(0, 5) var spread: float = 0 # Spread of each shot
+@export_range(1, 5) var shot_count: int = 1 # Amount of shots
+@export_range(0, 50) var knockback: int = 20 # Amount of knockback
+
+@export var min_knockback: Vector2 = Vector2(0.001, 0.001) # x for vertical knockback, y for horizontal knockback
+@export var max_knockback: Vector2 = Vector2(0.0025, 0.002) # x for vertical knockback, y for horizontal knockback
+
+@export_subgroup("Sounds")
+@export var sound_shoot: String # Sound path
+
+@export_subgroup("Crosshair")
+@export var crosshair: Texture2D # Image of crosshair on-screen

assets/kenney-fps/scripts/weapon.gd.uid

@@ -0,0 +1 @@
+uid://dg01pkkc1c5vd