feat(auth): make user icon clickable to trigger login when logged out

src/components/SidebarHeader.tsx

@@ -79,7 +79,12 @@ const SidebarHeader: React.FC<SidebarHeaderProps> = ({ onToggleCollapse, onLogou
           ariaLabel="Settings"
           variant="ghost"
         />
-        <div className="profile-avatar" title={getUserDisplayName()}>
+        <div 
+          className="profile-avatar" 
+          title={activeAccount ? getUserDisplayName() : "Login"}
+          onClick={!activeAccount ? (isConnecting ? () => {} : handleLogin) : undefined}
+          style={{ cursor: !activeAccount ? 'pointer' : 'default' }}
+        >
           {profileImage ? (
             <img src={profileImage} alt={getUserDisplayName()} />
           ) : (