chore: remove ignored Vite override

[janicduplessis]

Description

The root package.json still declares an npm-style Vite override, but pnpm 12 reads workspace overrides from pnpm-workspace.yaml, so the field is dead configuration. Vitest already resolves to stable Vite 8.2.2 despite the manifest claiming a rolldown-vite 7.3.1 substitution.

Solution

Remove the dead override rather than restoring the alias. The override was added while npm was substituting the temporary rolldown-vite package. The later migration from npm to pnpm left that npm-only top-level field in package.json, so the current pnpm 12 setup does not read it. See the introducing commit. Restoring the alias would also move the repository away from the current stable Vite 8 release, which already uses Rolldown.

The lockfile is unchanged. pnpm why vite resolves one version: Vite 8.2.2 through Vitest 5.0.0.

Test plan

• pnpm install --lockfile-only --offline --frozen-lockfile
• pnpm run format:check
• pnpm run lint
• pnpm run build
• pnpm run typecheck
• pnpm test (92 files, 3,515 tests)
• pnpm run test:e2e (20 tests)

Fixes #280