fix: center toast notifications on mobile screens

frontend/src/components/layout/toolbar.rs

@@ -41,7 +41,7 @@ pub fn Toolbar() -> impl IntoView {
                         <span class="hidden sm:inline">"Add Torrent"</span>
                         <span class="sm:hidden">"Add"</span>
                     </DialogTrigger>
-                    <DialogContent id="add-torrent-dialog">
+                    <DialogContent id="add-torrent-dialog" class="sm:max-w-[425px]">
                         <AddTorrentDialogContent />
                     </DialogContent>
                 </Dialog>

frontend/src/components/ui/toast.rs

@@ -170,9 +170,10 @@ pub fn Toaster(#[prop(default = SonnerPosition::default())] position: SonnerPosi
         <div 
             class=tw_merge!(
                 "fixed z-[100] flex gap-3 pointer-events-none w-full sm:w-[400px]",
+                "left-1/2 -translate-x-1/2 sm:left-auto sm:translate-x-0 px-4 sm:px-0", // Mobile centering fix
                 if is_bottom { "flex-col-reverse" } else { "flex-col" },
                 container_class,
-                "pb-[env(safe-area-inset-bottom)] pt-[env(safe-area-inset-top)] px-4 sm:px-0"
+                "pb-[env(safe-area-inset-bottom)] pt-[env(safe-area-inset-top)]"
             )
         >
             <For