fix: purple logo redesign (Hyper/Warp-inspired) + config UI rebrand + backgrounds.json

Logo: Stylized 'T' with purple gradient (#a855f7→#6d28d9), prompt
chevron, terminal dots, cursor glow. Hyper's superellipse corners,
Warp's refined edge. Replaces the neural-node cyan design.

- Config view name: "Wave Config" → "Terminolgy Config"
- All icon sizes regenerated (16-512px PNG, ICO, ICNS)
- Logo copied to public/logos/ and docs-mintlify/

Author: PhenixStar