UX polish pass 2: toasts, optimistic updates, mod update detection

- Install sonner; <Toaster> mounted in Providers, auto-tracks theme.
- Toasts replace inline result Alerts across ServerControls, PlayerManager,
  BackupManager, ModManager (install/remove/restore/delete/start/stop).
- PlayerManager: optimistic op/deop/whitelist/ban/pardon via onMutate +
  rollback; UI updates instantly before RCON round-trip.
- Modrinth search results now show author + "updated Xd ago" with full
  timestamp on hover; downloads on its own row.
- New /api/mods/updates endpoint: per-installed-mod Modrinth latest-version
  lookup (parallel, 30min memo). Amber "Update available" badge rendered
  next to installed mod rows when filenames differ.
- PlayerAvatar + Modrinth icons migrated to next/image (unoptimized, size
  hints) — fewer layout shifts.
- Login page surfaces ?error= + NextAuth error codes (CredentialsSignin,
  SessionRequired, etc.), preserves callbackUrl, adds autocomplete hints
  and role="alert". Wrapped in Suspense per Next 16 requirement.
- Snapshots + backups show relative "Xh ago" with exact timestamp on hover
  via new lib/time.ts helper.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/modrinth.ts

@@ -16,6 +16,9 @@ export type SearchResult = {
   icon_url: string;
   downloads: number;
   project_id: string;
+  author: string;
+  date_modified: string;
+  follows: number;
 };
 
 export type ModDownload = {
@@ -53,12 +56,15 @@ export async function searchMods(query: string): Promise<SearchResult[]> {
 
   const data = await res.json();
   return data.hits.map((h: Record<string, unknown>) => ({
-    slug: h.slug,
-    title: h.title,
-    description: h.description,
-    icon_url: h.icon_url || "",
-    downloads: h.downloads,
-    project_id: h.project_id,
+    slug: h.slug as string,
+    title: h.title as string,
+    description: h.description as string,
+    icon_url: (h.icon_url as string) || "",
+    downloads: (h.downloads as number) ?? 0,
+    project_id: h.project_id as string,
+    author: (h.author as string) || "",
+    date_modified: (h.date_modified as string) || "",
+    follows: (h.follows as number) ?? 0,
   }));
 }