chore(deps): upgrade Vite, Vitest, and tsx (#1569)

## Description

Upgrade Vite to 8.2.2, Vitest to 4.1.11, tsx to 4.23.13, and the Preact Vite preset to 2.10.6. Regenerate the adapter normalizers for Vite's updated Rolldown output and replace `__dirname` in the UI config with Node's ESM-native `import.meta.dirname`.

## Type of Change

- [ ] 🚀 Feature (new functionality)
- [ ] 🐛 Bug fix (fixes an issue)
- [ ] 📚 Documentation (docs-only change)
- [x] 🔧 Maintenance (refactor, chore, CI, etc.)
- [ ] 🧪 Testing (test-only changes)

## Testing

- [x] Relevant checks pass locally (`pnpm run tsc`, `pnpm run lint`, `pnpm run test`)
- [ ] Added/updated tests for changes
- [x] Manually verified changes work as expected

Additional validation: `pnpm run build` and `pnpm run test:adapter-normalizers`.

## Checklist

- [x] Code follows project style (`pnpm run lint` passes for touched files)
- [x] Self-review completed
- [x] Documentation updated (not needed; no user-facing behavior changed)
- [x] No new warnings introduced