fix: use vite build directly to skip nx typecheck dependency

nx build runs typecheck as a prerequisite (via @nx/vite/plugin config).
Use vite build directly for the main branch comparison build.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/pr-qa.yaml

@@ -104,8 +104,9 @@ jobs:
           git stash --include-untracked || true
           git checkout origin/main -- .
           pnpm install --frozen-lockfile
-          # Skip typecheck — main may have transient TS errors with our lockfile
-          pnpm exec nx build
+          # Use vite directly — skip typecheck since main may have TS errors
+          # when built with the PR branch's lockfile/deps
+          pnpm exec vite build
           mv dist dist-before
           # Restore PR branch
           git checkout - -- .