fix(web): Fix search bar not taking full width in TopBar

The right section of the TopBar had flex-1 unconditionally, splitting
the bar into two equal halves. The SearchBar could only fill the left
50%, leaving a large empty gap. Now the right section uses shrink-0
when no centerContent is present, letting the SearchBar fill the
remaining width.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: brendan-kellam

packages/web/src/app/[domain]/components/topBar.tsx

@@ -12,6 +12,7 @@ import { LogIn } from "lucide-react";
 import { useRouter } from "next/navigation";
 import { AppearanceDropdownMenu } from "./appearanceDropdownMenu";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
+import { cn } from "@/lib/utils";
 
 interface TopBarProps {
     domain: string;
@@ -58,7 +59,7 @@ export const TopBar = ({
                         {centerContent}
                     </div>
                 )}
-                <div className="flex-1 flex flex-row justify-end items-center gap-2">
+                <div className={cn("flex flex-row justify-end items-center gap-2", centerContent ? "flex-1" : "shrink-0")}>
                     {actions}
                     {session ? (
                         <MeControlDropdownMenu