feat(zaparoo): restore exit-launcher escape-to-stock behavior

When the alt launcher exits cleanly the OSD reverts to stock menu
items for the rest of the session (until reboot, which still routes
back to the Zaparoo menu RBF). Adds an s_escaped latch in
alt_launcher_configured() and gates the cores-picker root in
SelectFile() on is_menu() so the populated cores list works while the
Zaparoo menu RBF (in zaparoo/) is still loaded.

Author: wizzomafizzo

menu.cpp

@@ -413,8 +413,8 @@ void SelectFile(const char* path, const char* pFileExt, int Options, unsigned ch
 
 	if (Options & SCANO_CORES)
 	{
-		strcpy(selPath, get_rbf_dir());
-		if (strlen(get_rbf_name()))
+		strcpy(selPath, is_menu() ? "" : get_rbf_dir());
+		if (!is_menu() && strlen(get_rbf_name()))
 		{
 			if(strlen(selPath)) strcat(selPath, "/");
 			strcat(selPath, get_rbf_name());

support/zaparoo/alt_launcher.cpp

@@ -29,8 +29,14 @@ void alt_launcher_cfg_apply(void)
 	cfg.recents = 1;
 }
 
+static bool s_escaped = false;
+
 bool alt_launcher_configured(void)
 {
+	// After a clean exit / give-up, masquerade as not-configured so the rest
+	// of the OSD reverts to stock menu behavior for the rest of this session.
+	// Reboot re-execs MiSTer and resets this back to the file-existence cache.
+	if (s_escaped) return false;
 	static int cached = -1;
 	if (cached < 0) cached = FileExists(s_launcher_path, 0) ? 1 : 0;
 	return cached != 0;
@@ -231,6 +237,7 @@ static void return_to_normal_mode(void)
 	s_respawn_timer = 0;
 	s_crash_count = 0;
 	s_gave_up = true;
+	s_escaped = true;
 }
 
 static void reset_launcher_state(void)
@@ -240,6 +247,7 @@ static void reset_launcher_state(void)
 	s_crash_count = 0;
 	s_gave_up = false;
 	s_init_pending = false;
+	s_escaped = false;
 }
 
 static void kill_launcher(pid_t pid, int sig)