Install PS1 discs from zip and 7z archives, and show them as playable only with a firmware that runs them

A zip or 7z with a PS1 disc in it (a cue sheet and the files it names, a
.ccd with its .img and .sub, or a lone raw .bin or .img) is now installed
like a zipped ISO. A disc of several files goes into a folder of its own,
named after the cue sheet or .ccd. An ISO in the archive still takes
priority, and a lone .bin or .img only counts when nothing else does.

The game screen offers Play for a PS1 disc image only when the installed
firmware's POPS can run it: 3.95 to 6.61, with popsman.prx.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

UI/GameScreen.cpp

@@ -243,6 +243,9 @@ static bool FileTypeIsPlayable(IdentifiedFileType fileType) {
 	case IdentifiedFileType::PSP_UMD_VIDEO_ISO:
 		// Reverse logic.
 		return false;
+	case IdentifiedFileType::PSX_ISO:
+		// Through the firmware's POPS.
+		return InstalledFirmwareRunsPS1Discs();
 	default:
 		return true;
 	}