fix(ui): wire M keybind for star map toggle, clean up info panel

- Add _unhandled_key_input to main.gd: M toggles star_map.toggle_visible()
- Remove topology line from info panel (internal data, not player-facing)
- Cast aperture_count to int (was showing decimal point)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client/scripts/main.gd

@@ -141,6 +141,13 @@ func _ready() -> void:
 		debug_console.unpause_requested.connect(_on_dialogue_unpause_requested)
 
 
+func _unhandled_key_input(event: InputEvent) -> void:
+	if event.is_pressed() and not event.is_echo():
+		if event is InputEventKey and event.keycode == KEY_M:
+			if star_map:
+				star_map.toggle_visible()
+
+
 func _process(delta: float) -> void:
 	# Main game loop: poll snapshot, apply state, flush input
 	var snapshot: Variant = SimBridge.poll_snapshot()