feat(*): Add bot-vs-bot Spectate mode with main-menu entry, entropy-control flags (--ent-coef, --reset-std) for resumed training runs, and a Linux/3090 remote-training guide (TRAINING_LINUX.md)

Game/scripts/main_menu.gd

@@ -10,3 +10,7 @@ func _on_free_play_pressed() -> void:
 
 func _on_match_pressed() -> void:
 	get_tree().change_scene_to_file("res://scenes/match.tscn")
+
+
+func _on_spectate_pressed() -> void:
+	get_tree().change_scene_to_file("res://scenes/spectate.tscn")

Game/scripts/spectate_mode.gd

@@ -0,0 +1,54 @@
+extends GameMode
+
+# Spectate: bot vs bot exhibition — both ships are AI-driven so two trained
+# policies can be watched playing each other. Score tracking and kickoff
+# resets like Match, but no timer. R resets the ball, Esc returns to the menu.
+
+signal score_changed(score: Dictionary)
+
+@export_group("Team 0 bot")
+@export_file("*.json") var bot_a_model_path: String = ""
+@export_range(1, 60) var bot_a_reaction_ticks: int = 8
+@export_range(0.0, 1.0) var bot_a_action_noise: float = 0.0
+
+@export_group("Team 1 bot")
+@export_file("*.json") var bot_b_model_path: String = ""
+@export_range(1, 60) var bot_b_reaction_ticks: int = 8
+@export_range(0.0, 1.0) var bot_b_action_noise: float = 0.0
+
+var score := {0: 0, 1: 0}
+
+
+func _start() -> void:
+	spawn_ball()
+	var ship_a := spawn_ship(0, 0, _make_bot(bot_a_model_path, bot_a_reaction_ticks, bot_a_action_noise))
+	spawn_ship(1, 0, _make_bot(bot_b_model_path, bot_b_reaction_ticks, bot_b_action_noise))
+	spawn_camera_rig(ship_a)
+
+
+func _make_bot(model_path: String, reaction_ticks: int, action_noise: float) -> ShipController:
+	if not model_path.is_empty() and FileAccess.file_exists(model_path):
+		var bot := AIShipController.new()
+		bot.model_path = model_path
+		bot.reaction_ticks = reaction_ticks
+		bot.action_noise = action_noise
+		return bot
+	if not model_path.is_empty():
+		push_warning("SpectateMode: bot model not found at %s, spawning inert ship" % model_path)
+	return ShipController.new()  # inert placeholder
+
+
+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 _unhandled_input(event):
+	if event.is_action_pressed("reset_ball"):
+		reset_ball()
+	else:
+		super(event)

Game/scripts/spectate_mode.gd.uid

@@ -0,0 +1 @@
+uid://r86jia8qr60x