Add a Grid/List toggle to /projects

[notsointresting]

The browse page renders cards only. A dense list view is better for scanning many results.

WinnerRow in src/components/winner-card.tsx is already written and unused — wire it up.

Scope

• A toggle in src/components/results-toolbar.tsx that sets ?view=list / ?view=grid
• src/components/winner-browser.tsx reads the param and picks the renderer
• Default stays grid; the param must survive filtering and pagination like every other param
• Add a Playwright assertion in tests/e2e/smoke.spec.ts

Keep it simple — no client state beyond the URL.