refactor(*): Restructure game into reusable Arena/GameMode architecture with controller-driven ships, adding Free Play and Match modes

Game/scripts/match_mode.gd

@@ -0,0 +1,48 @@
+extends GameMode
+
+# Timed match: two teams, score tracking, kickoff resets after each goal.
+# The opponent ship is currently inert (base ShipController, zero action) —
+# it becomes the AI opponent once an AIShipController exists (see TODO.md),
+# and additional player ships once multiplayer lands.
+
+signal timer_updated(minutes: int, seconds: int)
+signal score_changed(score: Dictionary)
+
+@export var match_length_seconds := 150.0
+
+var score := {0: 0, 1: 0}
+var match_timer: Timer
+
+
+func _start() -> void:
+	spawn_ball()
+	var player_ship := spawn_ship(0, 0, PlayerShipController.new())
+	spawn_camera_rig(player_ship)
+	spawn_ship(1, 0, ShipController.new())  # inert placeholder opponent
+
+	match_timer = Timer.new()
+	match_timer.one_shot = true
+	match_timer.wait_time = match_length_seconds
+	match_timer.timeout.connect(_on_match_timer_timeout)
+	add_child(match_timer)
+	match_timer.start()
+
+
+func _process(_delta):
+	if match_timer and match_timer.time_left > 0:
+		var remaining := ceili(match_timer.time_left)
+		timer_updated.emit(floori(remaining / 60.0), remaining % 60)
+
+
+func _on_goal_scored(conceding_team: int) -> void:
+	var scoring_team := 1 - conceding_team
+	score[scoring_team] += 1
+	score_changed.emit(score.duplicate())
+	print("Goal for team %d! Score: %d - %d" % [scoring_team, score[0], score[1]])
+	reset_ball()
+	reset_ships()
+
+
+func _on_match_timer_timeout() -> void:
+	print("Full time! Final score: %d - %d" % [score[0], score[1]])
+	get_tree().change_scene_to_file(MAIN_MENU_SCENE_PATH)