Config UI redesign: usability and appearance

[gregjkal]

Summary

The Gateway config UI (the SPA in crates/gateway-config-ui) needs a proper design pass, both for usability and for appearance. Vinnie is not attached to the current layout and is happy for it to be rejiggered wholesale.

Requirements

From the #cppa-wg21-org design discussion on 2026-09-09, Vinnie's only two constraints:

1. Make it work great.
2. Make it look great.

Inputs

• The current UI borrowed heavily from Unsloth. The Unsloth models page is inspiration, not something to copy exactly.
• Cynthia's HTML mockup of a models page (2026-09-09, gist cprevatte/0692695fc28894b0e7e004b11d635354, promptforge-models.html) got strong positive reactions and is a candidate direction.
• Current tabs: Settings, Discover, Local, Remote, Profiles, Secrets.

Sub-issues

• Closed-weight provider catalog and API key UI: Gateway: closed-weight frontier provider catalog with per-provider API key UI #24
• Vendor logos throughout: Config UI: vendor logos throughout (SVG) #27