fix: top bar never wraps, and warn about 4K AV1 playback

The control row wrapped to a second line as the window narrowed. It is
now flex-nowrap with only the search field giving up width, and the
window minimum is raised to 1140x620 so the fixed controls always fit
beside the sidebar on one line.

Also lands the 4K AV1 warning in Settings. The earlier attempt at this
silently changed nothing — the replacement text did not match the file,
so the copy shipped unchanged while being reported as done.

src/components/TopBar.tsx

@@ -73,7 +73,7 @@ export default function TopBar({
     >
       {titleBarInset && <div data-tauri-drag-region className="h-9" />}
 
-      <div className="flex flex-wrap items-center gap-2 px-4 py-3">
+      <div className="flex flex-nowrap items-center gap-2 px-4 py-3">
         {sidebarHidden && (
           <button
             onClick={onShowSidebar}
@@ -92,14 +92,14 @@ export default function TopBar({
           value={search}
           onChange={(e) => onSearch(e.target.value)}
           placeholder="Search videos and channels"
-          className={`${INPUT} min-w-72 max-w-sm flex-1`}
+          className={`${INPUT} min-w-40 max-w-sm flex-1`}
         />
 
-        <span className="font-mono text-[11px] tabular-nums text-slate-400 dark:text-slate-500">
+        <span className="shrink-0 font-mono text-[11px] tabular-nums text-slate-400 dark:text-slate-500">
           {resultCount}
         </span>
 
-        <div className="flex-1" />
+        <div className="min-w-2 flex-1" />
 
         <Toggle active={downloadedOnly} onClick={() => onDownloadedOnly(!downloadedOnly)}
           disabled={!online}