RA/SwanStation opens handles and doesn't close them when RunAhead is active

Description

With Internal Run-Ahead active handles to .mcd Memory Card files are opened but never closed.

Expected behavior

close opened handles

Actual behavior

Handles to .mcd files are opened and never closed.
It seems to be based on how the game handles memory card loading. In Parasite Eve it opens those handles on every key press.

After a while the limit is reached (on macOS the default is 256) and nothing can be saved anymore, this includes RetroAchivements.

Steps to reproduce the bug

• In SwanStation Advanced core settings set Internal RunAhead to 2 frames.
• Restart RetroArch
• Play Parasite Eve (somehow this game triggers it more than other games)

run something like lsof -p "$(pgrep RetroArch)" -r 2 to see the open handles growing on each key press.

Version/Commit

• RetroArch: 1.15 stable
• RetroArch: 1.16 stable
• SwanStation latest
  It happens with the native AppleSilicon version and with the x86 version running through Rosetta.

Environment information

• OS: macOS 13.6
• MacBook Air M1

Reproduce on macOS with Internal Run-Ahead set to 2 frames, using the Parasite Eve steps and the lsof command to confirm that .mcd handles grow per key press. Trace the SwanStation memory-card loading path under RetroArch's Run-Ahead flow; done means opened handles are closed and repeated input no longer exhausts the process limit or prevents saves.