fix(storage-transfer): use z.string().url() for Zod 3 compat

z.url() is Zod 4 top-level syntax. The hoisted node_modules/zod
resolves to v3.25.76 (despite apps/sim/package.json declaring 4.3.6 —
a workspace resolution conflict), so z.url is undefined at runtime.

Trigger.dev's bundler eagerly evaluates all task-reachable modules at
startup and hits this with `external_exports.url is not a function`.
Next.js dev only evaluates routes per-request so the call site never
fires.

Quick fix: revert to the chained .string().url() form which works on
both Zod 3 and Zod 4 (deprecated in 4 but still supported). The
underlying version-resolution conflict is a separate cleanup.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: TheodoreSpeaks

apps/sim/lib/api/contracts/storage-transfer.ts

@@ -290,6 +290,7 @@ export const fileDownloadBodySchema = z
     isExecutionFile: z.boolean().optional(),
     context: downloadContextSchema.optional(),
     url: z
+      .string()
       .url()
       .refine((value) => ['http:', 'https:'].includes(new URL(value).protocol), {
         message: 'URL must use http or https',