feat(game): add free ball mode and improve ball state handling

* add Free Ball game mode and lobby selection
* refactor base mode ball state tracking for reaped/sunk balls
* add player ownership tracking and colored-ball support
* add initial 9-ball mode implementation
* update 8-ball and snooker modes to use base ball handling
* replicate ball linear velocity for multiplayer synchronization
* improve ball collision sound propagation and physics settings
* reenable game music and initialize game signals
* improve lobby input focus and mode selection behavior
* adjust cue impulse origin and default game mode

scenes/individual_parts/balls/balls.gd

@@ -5,8 +5,20 @@ func _ready() -> void:
 	for ball in bodies.get_children():
 		_set_ball_physics(ball)
 
+	setup_signals()
 	setup_multiplayer()
 
+func setup_signals() -> void:
+	# TODO: Need to refactor to not need server signal collision to
+	#       then play sounds. Maybe 2nd collider on ball that triggers?
+	#       Will that work since with clients we:
+	#       set_deferred("freeze", true)
+	#       set_physics_process(false)
+	#
+	#       Gods forgive me for my sins....
+	MessageBus.subscribe("balls_collide_signal", _on_balls_collide_signal)
+
+
 func _physics_process(_delta: float) -> void:
 	if not Globals.multiplayer_data.can_do_request_server_only():
 		return
@@ -28,8 +40,19 @@ func _on__ball_body_entered(ball: Node) -> void:
 	if not Globals.multiplayer_data.can_do_request_server_only():
 		return
 
-	if ball.name == "pool_table": return
+	if ball.name == "pool_table":
+		# TODO: Get/generate some type of sound/noise like corse texture of table
+		return
 
+	_play_collide_sound(ball)
+	MessageBus.emit_propagation_clients_only.rpc(
+		"balls_collide_signal", str( ball.get_path() )
+	)
+
+func _on_balls_collide_signal(ball: String) -> void:
+	_play_collide_sound( get_node(ball) )
+
+func _play_collide_sound(ball: Node) -> void:
 	var speed      = ball.linear_velocity.length()
 	var speed_norm = clamp(speed / max_speed, 0.0, 1.0)
 	var volume     = remap(

scenes/individual_parts/balls/balls_base.gd

@@ -20,6 +20,7 @@ class_name BallsBase extends Node3D
 
 var balls_moving: bool           = false
 
+
 func _set_ball_physics(ball: RigidBody3D) -> void:
 		var phy_mat = PhysicsMaterial.new()
 
@@ -29,11 +30,16 @@ func _set_ball_physics(ball: RigidBody3D) -> void:
 
 		ball.set_physics_material_override(phy_mat)
 
-		ball.axis_lock_linear_y = true
+		ball.axis_lock_linear_y    = true
 		ball.set_mass(ball_mass)
 		ball.set_linear_damp(2.04)
 		ball.set_angular_damp(1.44)
+
 		ball.set_use_continuous_collision_detection(true)
+		ball.contact_monitor       = true
+		# NOTE: How many balls can surround a single ball,
+		#       therefor worst case is 6 collisions. (think start of game)
+		ball.max_contacts_reported = 6
 
 		ball.body_entered.connect(_on__ball_body_entered)