fix(test): stop Vite's SSR transform from dropping zod's z export

[yange-siegenia]

On a clean checkout with the committed lockfile, bun run test fails to run essentially the whole suite. Every module that declares a zod schema throws on load, which is most of the server.

Cause

zod 4.4.3's entry point is:

import * as z from "./v4/classic/external.js";
export * from "./v4/classic/external.js";
export { z };
export default z;

Vite's SSR transform loses the z binding in that specific combination — a namespace import that is re-exported by name alongside an export * of the same module. import { z } from 'zod' therefore arrives as undefined, while import * as z from 'zod' still works.

Minimal reproduction:

import { z } from 'zod'
it('z is defined', () => {
  expect(typeof z?.string).toBe('function')  // fails: z is undefined
})

Fix

Add zod to the SSR optimizer's include list so esbuild pre-bundles it, which sidesteps the SSR transform and re-exports it correctly.

Two other plausible fixes were tried and do not work, which is why the comment records them:

• externalizing zod so Node loads it natively — still fails
• removing the SSR optimizer entirely — still fails

So this is specific to the SSR transform rather than to the optimizer being enabled.

Verification

Confirmed against main (currently ce3d245): the reproduction above fails without this change and passes with it.

Full suite against a real pgvector/pgvector:pg17 Postgres with migrations applied: 13,946 passing. The handful of remaining failures all pass when their files are run in isolation — they are pre-existing parallelism flakes under full-suite CPU contention, in auth components and email routing, unrelated to this change.

I hit this while working on something unrelated in a fork, and it looked worth sending upstream on its own.

[CLAassistant]

All committers have signed the CLA.