Restore the main menu when leaving the postgame host screen

The postgame host map picker opens without menu history. Give it the
existing main_menu_if_no_history flag used by the lobby so leaving the
last screen restores the main menu instead of leaving only the background.
Update the generator and generated XML together. Preserve OpenCE's
existing handlers; no MCC code or regression-test files are included.
This local menu change does not require a network version bump.

Resolved the fork cherry-pick against OpenCE main 8102e711 by adding only
the flag override. Windows portable release build passed. Existing menu
teardown, touch and web checks returned 28 passes and 6 failures: missing
m.lib/pthread.h and Windows path separators in POSIX-oriented tests.
Android and web build targets were unavailable locally. Checked generator
round-trip stability and git diff --check. The two simple wrappers were
regenerated through ce_menus.widget_xml from their exported XML fields;
the original PC tag inputs were unavailable. No upstream runtime game
session or Linux build was run. Earlier scripted runtime verification
was performed on the GulchCE implementation, not this upstream revision.

(cherry picked from commit c811c7f527d70d5476578ed88ea0edcef2269967)

port/assets/menus/ce/main_menu.multiplayer_type_select.connected.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- The PC version's menus: ui\shell\main_menu\multiplayer_type_select\connected (tools/ce_menus.py) -->
 <menus>
-	<widget name="main_menu/multiplayer_type_select/connected/connected_map_select_wrapper" width="640" height="480" flags="pass_unhandled_to_focused_child pause_game tag_controller_index force_handle_mouse">
+	<widget name="main_menu/multiplayer_type_select/connected/connected_map_select_wrapper" width="640" height="480" flags="pass_unhandled_to_focused_child pause_game main_menu_if_no_history tag_controller_index force_handle_mouse">
 		<child widget="main_menu/multiplayer_type_select/mp_map_select/mp_map_select_screen"/>
 	</widget>
 	<widget name="main_menu/multiplayer_type_select/connected/gametype_select_screen_wrapper" width="640" height="480" flags="pass_unhandled_to_focused_child pause_game">

tools/port_settings.py

@@ -618,6 +618,11 @@ MAP_KIND_CHOOSER = "main_menu/new_select/list_item_0_map_kind"
 # changes to the PC version's widgets (by our names): attributes set, all
 # their handlers replaced, children added, game data inputs added
 WIDGET_PATCHES = {
+    # The host returns here after a round with no menu history. Back must
+    # reopen the main menu when it closes the last screen, as the lobby does.
+    f"{MT}/connected/connected_map_select_wrapper": {"set": {
+        "flags": "pass_unhandled_to_focused_child pause_game main_menu_if_no_history tag_controller_index force_handle_mouse",
+    }},
     # (the profile settings' picture: on Gamepad Setup's row, the profile's
     # button settings, BITMAP_FRAMES; menu_functions.c's
     # profile_gamepad_layout)