Replace pinned Vite 7 with latest Vite version #903
Description
In #900, Vitest was updated to 4.1.2, but this introduced a problem. Vitest 4.1.0+ brings in Vite 8 by default, which switches to OXC for parsing. OXC doesn't yet fully support current ECMAScript syntax, namely, TC39 decorators (admittedly, at stage 3, but already supported by TypeScript), causing syntax errors on otherwise valid code, see vitest-dev/vitest#9876.
As a workaround, Vite 7 was pinned in #900. This issue tracks removing that pin and upgrading to the latest Vite once the upstream ecosystem issues are resolved. We don't want to hang behind on an old major version indefinitely, nor do we want to use Babel or some other transformer.
Blocked by:
- transformer: ecma decorators oxc-project/oxc#9170
- Add decorators tests tc39/test262#4103
- Regression in 4.1.0: (method) decorators not accepted in class defined in test files vitest-dev/vitest#9876
Once these are resolved, or Vitest otherwise addresses the regression, the Vite 7 pin should be removed.