Add external-flash overlay app platform

App/app/main.c

@@ -31,8 +31,11 @@
 #include "app/spectrum.h"
 #endif
 
-#ifdef ENABLE_FEAT_F4HWN_GAME
-#include "app/breakout.h"
+#if defined(ENABLE_FEAT_F4HWN_GAME) && !defined(ENABLE_FEAT_F4HWN_OVERLAY_APPS)
+#include "app/breakout.h"   // resident game only; the overlay path uses app_menu.h
+#endif
+#ifdef ENABLE_FEAT_F4HWN_OVERLAY_APPS
+#include "apps/app_menu.h"
 #endif
 
 #include "audio.h"
@@ -269,9 +272,15 @@ static void processFKeyFunction(const KEY_Code_t Key, const bool beep)
             break;
 
         case KEY_7:
-#ifdef ENABLE_FEAT_F4HWN_GAME
+            // F + 7 opens the overlay-apps menu when that support is built;
+            // otherwise it launches the resident game (GAME); otherwise VOX.
+#if defined(ENABLE_FEAT_F4HWN_OVERLAY_APPS) || defined(ENABLE_FEAT_F4HWN_GAME)
             if (!beep) {
-                APP_RunBreakout();
+#if defined(ENABLE_FEAT_F4HWN_OVERLAY_APPS)
+                APP_MenuOpen();            // overlay-apps selector
+#else
+                APP_RunBreakout();         // resident game (no overlay support)
+#endif
             } else {
 #endif
 #ifdef ENABLE_VOX
@@ -279,7 +288,7 @@ static void processFKeyFunction(const KEY_Code_t Key, const bool beep)
 //#else
 //              toggle_chan_scanlist();
 #endif
-#ifdef ENABLE_FEAT_F4HWN_GAME
+#if defined(ENABLE_FEAT_F4HWN_OVERLAY_APPS) || defined(ENABLE_FEAT_F4HWN_GAME)
             }
 #endif