fix(ci): pin rolldown binding version to match checked-out source (#597)

## Summary

- Pin the rolldown binding version in `download-rolldown-binaries` action to match the checked-out source, instead of fetching the latest from npm
- Remove the `VITE_TEST_BUILD=1 vp run tests-e2e#test` line from VitePress E2E (fix in follow-up #599)

## Background on the VitePress `VITE_TEST_BUILD=1` failure

There is a bug in vite's `ModuleRunner.directRequest()` where `dynamicRequest` uses the raw `url` parameter for relative path resolution (`posixResolve(posixDirname(url), dep)`). When a module is loaded via a `file://` URL (e.g. VitePress's `import(pathToFileURL(entryPath).href)`), `pathe.resolve` doesn't recognize `file://` as absolute, producing malformed paths like `<cwd>/file:<path>`.

### Why it doesn't happen with vanilla vitest

With vanilla vitest, VitePress is a regular npm dependency living in `node_modules/`. Vitest's externalization check (`id.includes('/node_modules/')`) returns `true`, so VitePress is **externalized** — loaded via native Node.js `import()` which handles `file://` URLs correctly. The module runner's `dynamicRequest` is never involved.

In vite-plus's ecosystem-ci, VitePress is a `workspace:*` dependency. Its files aren't in `node_modules/`, so it's **inlined** (SSR-transformed). Its `import(pathToFileURL(...))` becomes `__vite_ssr_dynamic_import__('file://...')`, which flows through `dynamicRequest` and hits the bug.

### Why it didn't fail before #588

Before #588, `vp test` commands had caching enabled. When CI ran `vp run tests-e2e#test` (without `VITE_TEST_BUILD`), it succeeded and created a cache entry. The next step `VITE_TEST_BUILD=1 vp run tests-e2e#test` ignored `VITE_TEST_BUILD` since it wasn't in the fingerprinted envs, hit the cache, and `vp test` never actually ran with `VITE_TEST_BUILD=1`. #588 disabled caching on `vp test` commands, so the second step actually ran for the first time and exposed the bug.

The fix is in follow-up #599.

Author: branchseer

.github/actions/download-rolldown-binaries/action.yml

@@ -28,7 +28,17 @@ runs:
           export TARGET="darwin-arm64"
         fi
 
-        export VERSION=$(npm view --json rolldown | jq -r '.version')
+        # Pin to the version from checked-out rolldown source to avoid mismatch
+        # between JS code (built from source) and native binary (downloaded from npm).
+        # Falls back to npm latest only when rolldown source isn't cloned yet
+        # (e.g., the standalone download-previous-rolldown-binaries job).
+        if [ -f "./rolldown/packages/rolldown/package.json" ]; then
+          export VERSION=$(node -p "require('./rolldown/packages/rolldown/package.json').version")
+          echo "Using rolldown version from source: ${VERSION}"
+        else
+          export VERSION=$(npm view --json rolldown | jq -r '.version')
+          echo "Warning: rolldown source not found, using npm latest: ${VERSION}"
+        fi
         npm pack "@rolldown/binding-${TARGET}@${VERSION}"
         tar -xzf "rolldown-binding-${TARGET}-${VERSION}.tgz"
         if [ -d "./rolldown/packages/rolldown/src" ]; then

.github/workflows/e2e-test.yml

@@ -212,7 +212,6 @@ jobs:
               vp run build
               vp test run -r __tests__/unit
               vp run tests-e2e#test
-              VITE_TEST_BUILD=1 vp run tests-e2e#test
               vp run tests-init#test
           - name: tanstack-start-helloworld
             node-version: 24