mfc: detect 2025 version (#416)

## Link to GitHub Issue, if one exists
n/a

## Description of change
They moved some DLLs around so MFC wasn't being auto-detected, and I/O
hooks were not being performed. Fix that.

## Testing
The game boots into test menu, some i/o works, touch doesn't, not
playable yet.

src/spice2x/launcher/launcher.cpp

@@ -1676,6 +1676,14 @@ int main_implementation(int argc, char *argv[]) {
                 attach_io = true;
                 attach_mfc = true;
                 break;
+
+            // Mahjong Fight Club - 2025?
+            // they removed allinone.dll and moved i/o into system.dll
+            } else if (check_dll("system.dll") && fileutils::file_exists("data/mfc.ini")) {
+                avs::game::DLL_NAME = "system.dll";
+                attach_io = true;
+                attach_mfc = true;
+                break;
             }
 
             // FutureTomTom