Fix production CSS assets before v0.2.0

[gcharang]

Summary

• move global CSS from an explicit Vite URL import to TanStack Start route-asset discovery
• run the existing production asset smoke check inside the clean web image build
• synchronize browser interactions on hydration under cold dev-server builds

Root cause

The first exact-master live gate stopped before credentials were minted or provider calls were made. Its clean web image emitted one client CSS file but the server bundle referenced a different, nonexistent hash. The root route used a CSS ?url import, so the client and SSR environments independently derived asset URLs. A side-effect CSS import lets TanStack Start source the SSR stylesheet link from the client build manifest.

Verification

• make web-check
• CHOKIDAR_USEPOLLING=1 make playwright: 20 passed, paid live test skipped
• make docker-build-web: clean Alpine image build and embedded production smoke passed
• TEST_POSTGRES_PORT=55433 CHOKIDAR_USEPOLLING=1 make ci HELM=/tmp/vectorless-helm-v4.2.3.8EbmRp/linux-amd64/helm
• git diff --check