Pass 3 first slice: mod update action, error boundaries, a11y, palette

- New POST /api/mods/update SSE route: per-file Modrinth lookup → snapshot →
  download latest → swap old jar → restart + verify (if server-side) →
  rebuild modpack, with automatic rollback on any failure.
- ModManager: "Update" button next to each mod with an available update,
  plus "Update all (N)" in the installed list header. Reuses the existing
  install timeline UI (same event shape). SSE reader extracted as
  consumeSSE helper.
- Error boundaries: app/error.tsx (scoped), app/admin/error.tsx (admin
  subtree retry), app/not-found.tsx, app/global-error.tsx (hard-fail
  fallback with inline styles, no app shell dependency).
- A11y sweep: aria-pressed + aria-label on LogViewer level chips and
  ModManager side filter; aria-label on admin TabsList; skip-to-content
  link in Navbar targeting <main id="main"> on public + admin pages;
  role/aria-live on install/update timeline; global Esc in ModManager
  clears open confirm prompts and exits search/review wizard steps.
- Command palette (cmdk): global Ctrl/⌘+K dialog mounted in Providers.
  Navigate admin tabs, toggle theme, start/stop/restart server, create
  backup, re-check mod updates, jump to any cached mod/player/snapshot/
  backup. Auth-aware — public users see only Home / Log in / Theme.
- AdminTabs listens to hashchange so palette navigation updates the
  active tab live.

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

components/AdminTabs.tsx

@@ -34,6 +34,15 @@ export function AdminTabs() {
     if (saved && TABS.some((t) => t.value === saved)) setValue(saved);
   }, []);
 
+  useEffect(() => {
+    const onHash = () => {
+      const h = window.location.hash.replace("#", "");
+      if (h && TABS.some((t) => t.value === h)) setValue(h);
+    };
+    window.addEventListener("hashchange", onHash);
+    return () => window.removeEventListener("hashchange", onHash);
+  }, []);
+
   useEffect(() => {
     if (!mounted) return;
     localStorage.setItem("admin-tab", value);
@@ -48,7 +57,10 @@ export function AdminTabs() {
       onValueChange={(v) => setValue(v as string)}
       className="w-full"
     >
-      <TabsList className="flex w-full flex-wrap h-auto sm:h-9 gap-1 p-1 overflow-x-auto justify-start sm:justify-center">
+      <TabsList
+        aria-label="Admin sections"
+        className="flex w-full flex-wrap h-auto sm:h-9 gap-1 p-1 overflow-x-auto justify-start sm:justify-center"
+      >
         {TABS.map((t) => (
           <TabsTrigger key={t.value} value={t.value} className="text-xs sm:text-sm">
             {t.label}