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

controllers/game/modes/base_mode.gd

@@ -4,26 +4,56 @@ class_name BaseMode extends Node
 #       these signals to handle game related rules regarding ball sinks.
 
 
+var player_1_points: int = 0
+var player_2_points: int = 0
+
 var ball_state   := generate_ball_state()
 var balls_sunk   := []
 var balls_reaped := []
 
 var STATE: Dictionary = {
-	"sunk": false
+	"sunk":   false,
+	"reaped": false,
+	"player": ""
 }
 
+var COLORED_BALLS: Array = [
+	"yellow_ball", "green_ball", "brown_ball",
+	"blue_ball",   "pink_ball",  "black_ball"
+]
+
 func generate_ball_state() -> Dictionary:
 	var state := {}
-	for i in range(1, 16):
-		state["%02d_ball" % i] = STATE
+
+	for ball_name: String in COLORED_BALLS:
+		state[ball_name]       = STATE.duplicate_deep()
+
+	for i: int in range(1, 16):
+		state["%02d_ball" % i] = STATE.duplicate_deep()
 
 	return state
 
-func reap_ball(_ball: Node3D) -> void:
-	assert(false, "This method needs to be overridden...")
+func is_colored_ball(ball_name: String) -> bool:
+	return ball_name in COLORED_BALLS
 
-func process_ball(_ball: Node3D) -> void:
-	assert(false, "This method needs to be overridden...")
+func which_player() -> String:
+	return                                                                           \
+		"Player 1"                                                                   \
+	if                                                                               \
+		Globals.game_data.client1 == Globals.multiplayer_data.current_turn_player_id \
+	else                                                                             \
+		"Player 2"
+
+func reap_ball(ball: Node3D) -> void:
+	balls_reaped.append(ball.name)
+	ball_state[ball.name]["reaped"] = not ball_state[ball.name]["reaped"]
+	ball_state[ball.name]["player"] = which_player()
+
+func process_ball(ball: Node3D) -> void:
+	balls_sunk.append(ball.name)
+
+	ball_state[ball.name]["sunk"]   = not ball_state[ball.name]["sunk"]
+	ball_state[ball.name]["player"] = which_player()
 
 func handle_switch_user() -> void:
 	assert(false, "This method needs to be overridden...")