perf-kit: no rolldown found when vite bundles it (Vite+) #11504

What happens

With Vite+, vite is an alias of @voidzero-dev/vite-plus-core, which bundles rolldown inside its own dist/rolldown/ (its package.json records the version under bundledVersions.rolldown). No rolldown package resolves from vite, so @rolldown/perf-kit@0.1.0 cannot see it:

• worker-config prints no rolldown package resolves from <app> - install the app's dependencies first (vite >= 8 brings rolldown). (appRolldown in lib/rolldown-support.mjs).
• The generated perf-kit.vite.config.ts throws at build: Cannot find module 'rolldown/package.json' from '…/@voidzero-dev/vite-plus-core/package.json' (assertReportMode in the lib/worker/config.mjs template).

The bundled rolldown has the report mode: vite-plus-core@1.5.0 bundles rolldown 1.2.16, and devtools: { mode: 'report' } writes the report. With the guard bypassed, worker-scan, why and what-if work.

Reproduce

A project on vite-plus@1.5.0 ("vite": "npm:@voidzero-dev/vite-plus-core@^1.5.0") with a Cloudflare Worker:

npx perf-kit worker-config --app .
npx vite build --config perf-kit.vite.config.ts

Suggested fix

When rolldown/package.json does not resolve from vite and vite has a dist/rolldown/, probe vite's own dist for the report mode, and take the version from bundledVersions.rolldown. rolldown-install should refuse that case, since it would copy a rolldown package over vite itself. We carry this as a local patch (about 30 lines, in appRolldown, installCheckoutRolldown and the shim's assertReportMode) and can open a PR if that helps.