add .model extension for spiece.model file from tokenizer

src/lib/check-filename.ts

@@ -4,9 +4,10 @@ export function checkFilename(filename: string) {
 		!filename.endsWith('.json') &&
 		!filename.endsWith('.gguf') &&
         !filename.endsWith('.txt') &&
+        !filename.endsWith('.model') &&
 		!filename.endsWith('/')
 	) {
-		throw new Error('Files must have a .safetensors, .txt, .gguf or .json extension');
+		throw new Error('Files must have a .safetensors, .txt, .gguf or .json or .model extension');
 	}
 
 	const split = filename.split('/');