Queue native collection launches before async placement

src/lib/ui/components/NativeHostSelection.svelte

@@ -15,7 +15,8 @@
     const latest = $derived(latestGameFiles(libraries));
 
     function cacheReady(game: ZombieGame) { return !!latest[game]?.caches.some(cache => eligible.some(host => host.id === cache.hostId) && ['ready', 'outdated'].includes(cache.status)); }
-    $effect(() => { ready = !loading && !error && games.length > 0 && games.every(game => selection.libraryIds[game] === latest[game]?.id && cacheReady(game)); });
+    $effect(() => { ready = !loading && !error && /^[a-zA-Z0-9][a-zA-Z0-9._/:@-]{0,499}$/.test(selection.image)
+        && games.length > 0 && games.every(game => !!latest[game]?.id && selection.libraryIds[game] === latest[game]?.id); });
     $effect(() => {
         if (disabled || !defaultRuntimeImage || runtimeSelection === selection) return;
         if (!selection.image) selection.image = defaultRuntimeImage;
@@ -42,14 +43,14 @@
     <div class="title"><h3>Host and game files</h3><button type="button" disabled={disabled || loading} onclick={() => { onchange?.(); void load(); }}>Refresh hosts</button></div>
     {#if error}<p role="alert" class="error">{error}</p>{/if}
     {#if loading}<p role="status">Loading host readiness and game files…</p>{/if}
-    <p>Hosts are assigned automatically. We check available capacity before accepting a launch and choose the least loaded eligible host when provisioning starts.</p>
+    <p>Hosts are assigned when provisioning starts. You can queue launches while hosts are busy or preparing; each server waits for an eligible host and available capacity.</p>
     {#if !loading && !hosts.length}<p><a href="/hosts" target="_blank" rel="noopener">Add a host</a>. Its runtime and latest T5 and T6 files will be prepared automatically.</p>{/if}
     {#if !loading}{#each games as game}
         <div class="game-files">
             <strong>{game === 't5' ? 'Black Ops I (T5)' : 'Black Ops II (T6)'} files</strong>
             {#if latest[game]}
                 <p>Latest upload · {$timeFormat.dateTime(latest[game]?.publishedAt ?? latest[game]?.createdAt)}</p>
-                <p role="status">{cacheReady(game) ? 'Latest files ready on an eligible host.' : 'Waiting for a host to prepare the runtime and latest files automatically.'}</p>
+                <p role="status">{cacheReady(game) ? 'Latest files ready on an eligible host.' : 'Launches can be queued now and will wait for a host to prepare the runtime and latest files.'}</p>
             {:else}
                 <p>No files uploaded yet. <a href="/game-files" target="_blank" rel="noopener">Upload {game.toUpperCase()} files</a> to prepare your hosts.</p>
             {/if}