Revert "Remove "direct" bin file handling"

This reverts commit a2d97dfb5f.

src/BizHawk.Client.Common/RomLoader.cs

@@ -485,6 +485,34 @@ namespace BizHawk.Client.Common
 						game.System = VSystemID.Raw.SGB;
 					}
 					break;
+				case VSystemID.Raw.PSX when ext is ".bin":
+					const string FILE_EXT_CUE = ".cue";
+					var cuePath = TempFileManager.GetTempFilename(friendlyName: "syn", dotAndExtension: FILE_EXT_CUE, delete: false);
+					DiscMountJob.CreateSyntheticCue(cueFilePath: cuePath, binFilePath: file.Name);
+					var gameBak = game;
+					var nextEmulatorBak = nextEmulator;
+					try
+					{
+						if (LoadDisc(
+							path: cuePath,
+							nextComm,
+							new(cuePath),
+							ext: FILE_EXT_CUE,
+							forcedCoreName: forcedCoreName,
+							out nextEmulator,
+							out game))
+						{
+							return;
+						}
+						Console.WriteLine("synthesised .cue failed to load");
+					}
+					catch (Exception e)
+					{
+						Console.WriteLine($"synthesised .cue failed to load: {e}");
+					}
+					game = gameBak;
+					nextEmulator = nextEmulatorBak;
+					break;
 			}
 			var cip = new CoreInventoryParameters(this)
 			{

src/BizHawk.Emulation.DiscSystem/DiscMountJob.cs

@@ -230,5 +230,10 @@ namespace BizHawk.Emulation.DiscSystem
 			var len = new FileInfo(binFilePath).Length;
 			return GenerateCue(binFilename, isMode2: len % 2048 is not 0 && len % 2352 is 0);
 		}
+
+		public static void CreateSyntheticCue(string cueFilePath, string binFilePath)
+			=> File.WriteAllText(
+				path: cueFilePath,
+				contents: GenerateCue(binFilename: binFilePath/*abs is fine here*/, binFilePath: binFilePath)); //TODO as with .iso, may want to try both
 	}
 }