Fix: Update bun runtime models.ts to use type-only imports

Co-authored-by: Yiming Cao <ymc9@users.noreply.github.com>

Author: claude[bot]

tests/runtimes/bun/schemas/models.ts

@@ -6,6 +6,6 @@
 /* eslint-disable */
 
 import { type SchemaType as $Schema } from "./schema";
-import { type ModelResult as $ModelResult } from "@zenstackhq/orm";
+import type { ModelResult as $ModelResult } from "@zenstackhq/orm";
 export type User = $ModelResult<$Schema, "User">;
 export type Post = $ModelResult<$Schema, "Post">;