Remove invalid oxc.transform config from browser vitest config

OxcOptions doesn't have a transform key — Vite 8 handles TSX automatically.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/planner/vitest.browser.config.ts

@@ -11,9 +11,6 @@ import { playwright } from "@vitest/browser-playwright";
 // (.github/workflows/update-visual-snapshots.yml), triggered manually or
 // by adding the `update-snapshots` label to a PR.
 export default defineConfig({
-  oxc: {
-    transform: { react: {} },
-  },
   resolve: {
     alias: {
       "~": resolve(import.meta.dirname, "app"),