The finding: main is the right base — already soft corners + no Secrets sidebar. It needs exactly 4 render-fixes (Emily→Radar, remove banner, remove Floom logo, show Brain dropzone) + the ~20 open feature PRs applied on top. No boxy --radius-ui (that was only the staging branch).
Overview
BASELINE — main (what we build on)

TARGET — the good reference

corners soft ✓no Secrets ✓Emily Star → Radarremove Floom logo
Brain
BASELINE — main (what we build on)

TARGET — the good reference

corners soft ✓no Secrets ✓remove bannershow dropzone