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/pages/sessions.tsx

@@ -238,15 +238,6 @@ export const SessionsPage = () => {
     }
   };
 
-  const handleResumeLast = async () => {
-    if (!lastSession) return;
-    // Find the project and repo IDs
-    const project = projects.find((p) => p.name === lastSession.project_name);
-    if (project) {
-      navigate(`/projects/${project.id}`);
-    }
-  };
-
   return (
     <section className="stack sessions-page">
       <div className="page-header">