fix(ui): pin NODE_ENV=test in vitest config so prod env shells pass (RAN-40) (#81)

React 19 ships separate CJS builds and selects between them via
process.env.NODE_ENV at require-time; the production build omits `act`,
which @testing-library/react needs. Any developer whose shell exports
NODE_ENV=production (CI-adjacent shells, the Paperclip agent harness, etc.)
would see 78/97 tests fail with `TypeError: React.act is not a function`,
even though CI runners (NODE_ENV unset) pass.

Vitest already does `process.env.NODE_ENV ||= 'test'`, but only when unset;
when it's already `production` it's preserved, hence the bug. `--mode test`
also doesn't override an already-set NODE_ENV in vitest 4.

Force NODE_ENV=test at the top of vitest.config.ts before any worker forks
so the test suite is deterministic regardless of caller env.

Verified locally:
- NODE_ENV=production npm --prefix ui run test → 97/97 pass
- NODE_ENV=production npm --prefix ui run test:coverage → coverage generated
- NODE_ENV unset npm --prefix ui run test → 97/97 pass (CI parity)

Co-authored-by: Paperclip <noreply@paperclip.ing>

Author: aksOps

ui/vitest.config.ts

@@ -2,6 +2,12 @@ import { defineConfig } from "vitest/config";
 import react from "@vitejs/plugin-react";
 import { resolve } from "path";
 
+// React 19's CJS entry picks production vs development at require-time off
+// NODE_ENV; the production build omits `act`. Force the test build before any
+// worker forks so callers with NODE_ENV=production (CI-adjacent shells, the
+// Paperclip agent harness) get the same result as bare `npm test`.
+process.env.NODE_ENV = "test";
+
 export default defineConfig({
   plugins: [react()],
   resolve: {