[Bug] EmulatorJS defaults to .cue instead of playable .iso in CUE+ISO ROM directories[Bug] Bug title

RomM version 5.1.0

Describe the bug I encountered a reproducible in-browser playback problem with a 3DO title stored as a CUE+ISO pair. RomM correctly identifies the game as a single title with two associated files, but on first opening the EmulatorJS player it defaults to the .cue member. Launching in that state starts the Opera core, but the game itself is not attached; I am left at the generic RetroArch/Opera menu.

The same title boots normally if I return to the RomM player, manually change the file selector from the .cue to the corresponding .iso, leave the same verified 3DO BIOS selected, and launch again.

The specific test case was:

Hell - A Cyberpunk Thriller (1994) (Take 2) (US) [!].cue Hell - A Cyberpunk Thriller (1994) (Take 2) (US) [!].iso

The CUE is a normal descriptor referencing the ISO. The ISO itself is a valid 3DO Opera filesystem image.

I initially suspected firmware, but that appears to be independent of the problem. RomM detects and verifies my OEM 3DO BIOS files, and panafz1.bin is selected and persists for the platform. With that same BIOS:

.cue selected -> Opera starts, game does not .iso selected -> game boots normally

Steps to reproduce

Add a 3DO game represented in RomM by a .cue and its corresponding .iso. Scan the library normally. Open the game's EmulatorJS player without previously making a per-ROM file selection. Observe that the file selector defaults to the .cue. Select a valid 3DO BIOS and press Play. Opera starts without loading the game. Return to the player, select the .iso instead, and press Play using the same BIOS. The game boots normally.

Expected behavior RomM should not default to a descriptor file in a way that causes only the descriptor to be handed to EmulatorJS without the payload it references.

I do not think globally preferring .iso or excluding .cue would be an appropriate solution, because CUE files are meaningful and necessary for other disc layouts and platforms. The underlying issue seems to be that the default member selection treats the CUE and its referenced image as interchangeable independent playback candidates.

Ideally, RomM would either:

understand the descriptor/payload relationship and provide the necessary files together; or when a directly bootable image is available, choose an appropriate playable member by default rather than simply selecting the first associated file.

I am primarily reporting the reproducible behavior rather than prescribing the implementation.

Additional context Manually selecting the ISO is a reliable workaround. Once selected, RomM remembers the file choice for that individual game, so this primarily affects the initial/default playback path.

I can provide additional filesystem layout, CUE contents, browser diagnostics, or logs if useful.