feat: add styles and polish for unified session list components

- Add CSS styles for SessionCard and SessionList components
- Add responsive styles for mobile viewport
- Fix TypeScript errors (remove unused port property)
- Fix ESLint errors (remove unused imports and variables)

Refs: session-list-overhaul tasks 5-6

apps/web/src/components/session-card.tsx

@@ -110,9 +110,6 @@ export function SessionCard({
               </a>
             </p>
           )}
-          {session.port && session.status === "running" && (
-            <p className="muted session-card-meta">Port: {session.port}</p>
-          )}
           {session.created_at && (
             <p className="muted session-card-meta">
               Created: {new Date(session.created_at).toLocaleDateString()}