Fix keyboard input not working on Windows client

Added explicit window focus grab after connecting (lan-bootstrapper.gd)
so keyboard input is properly received by the input system.
Also added diagnostic debug prints to trace input pipeline.

examples/shared/scripts/lan-bootstrapper.gd

@@ -72,6 +72,9 @@ func join():
 	print("Client started")
 	connect_ui.hide()
 	
+	# Ensure game window has keyboard focus for input
+	get_window().grab_focus()
+	
 	# Only start manually if NetworkEvents is not handling it (e.g. multiplayer-simple)
 	if not NetworkEvents.enabled:
 		NetworkTime.start()
@@ -80,8 +83,14 @@ func _enter_tree():
 	# Hide and show UI as appropriate
 	# These handlers are necessary, since the game could have started via
 	# autoconnect, or any other method
-	NetworkEvents.on_client_start.connect(func(__): connect_ui.hide())
-	NetworkEvents.on_server_start.connect(func(): connect_ui.hide())
+	NetworkEvents.on_client_start.connect(func(__):
+		connect_ui.hide()
+		get_window().grab_focus()
+	)
+	NetworkEvents.on_server_start.connect(func():
+		connect_ui.hide()
+		get_window().grab_focus()
+	)
 	NetworkEvents.on_client_stop.connect(func(): connect_ui.show())
 	NetworkEvents.on_server_stop.connect(func(): connect_ui.show())