feat: hashing css names by filename

picks either filename or component name or css texts

packages/svelte/src/compiler/validate-options.js

@@ -70,8 +70,10 @@ const component_options = {
 		return input;
 	}),
 
-	cssHash: fun(({ css, hash }) => {
-		return `svelte-${hash(css)}`;
+	cssHash: fun(({ css, filename, name, hash }) => {
+		//either use extracted filename or component name 
+		filename = filename ? filename.replace(/^.*[\\/]/, '') : name;
+		return `svelte-${hash(filename ?? css )}`;
 	}),
 
 	// TODO this is a sourcemap option, would be good to put under a sourcemap namespace