Run executables directly (#645)

- Apps can be launched directly from file paths (including Files app support)
- Added executable detection to identify unsupported or invalid binaries before launch.
- App startup is now streamlined through separate registered-app and direct-execution interfaces.
- Existing app launch points were migrated to the updated startup APIs.

Modules/app-module/include/app/stream.h

@@ -37,7 +37,7 @@ struct AppStream {
     AppInstanceId producer_id;
     TaskHandle_t producer_task;
     /** fd this stream is installed at in producer_id's fd table; set by
-     * app_stream_subscribe()/app_manager_start_with_streams(), used by
+     * app_stream_subscribe()/app_start_with_streams(), used by
      * app_stream_unsubscribe() to find it again. */
     int producer_fd;