feat(web): FE overhaul — SWR centralized data layer + dashboard + islands

- Add SWR foundation (lib/fetcher, lib/swr, lib/api) with typed
  hooks: useSections/useDocuments/useSearch/useRelated/useRevisions/useQueueStatus
- Replace ad-hoc useEffect+fetch in Header/Sidebar/CommandMenu/search
  with SWR (dedup 4s, focus throttle 10s, debounced search 180ms)
- Doc page: RelatedGrid + RevisionList as SWR client islands (RSC hero stays)
- DocForm: SWR mutate on create/update for live sidebar invalidation
- New APIs: /api/related, /api/revisions, /api/tags, /api/queue/status,
  /api/docs filtering (?section=&status=)
- New UI: DocumentCard, SectionCard, SearchBar, TagCloud, QueueBadge,
  EmptyState, dashboard (/dashboard with QueueStrip live + section stats)
- Layout wraps SWRProvider; no TanStack code (SWR-only per spec)
- Verified: next build passes (16.3.4 Turbopack), no manual fetch sprawl remains

Co-Authored-By: internal-model

apps/web/app/components/RelatedGrid.tsx

@@ -0,0 +1,53 @@
+"use client";
+
+import Link from "next/link";
+import { useRelated } from "@/hooks/useRelated";
+import { getSectionMeta } from "@mcpedia/config/sections";
+import { Sparkles } from "lucide-react";
+
+export default function RelatedGrid({ slug }: { slug: string }) {
+  const { related, isLoading, error } = useRelated(slug, 4);
+
+  if (isLoading) {
+    return (
+      <div className="grid grid-cols-1 sm:grid-cols-2 gap-3 animate-pulse">
+        {Array.from({ length: 4 }).map((_, i) => (
+          <div key={i} className="h-24 bg-[var(--bg-surface)] border border-[var(--border-color)] rounded-lg" />
+        ))}
+      </div>
+    );
+  }
+
+  if (error || related.length === 0) return null;
+
+  return (
+    <aside className="mt-12 pt-8 border-t border-[var(--border-color)]">
+      <div className="flex items-center gap-2 mb-3.5">
+        <Sparkles className="w-4 h-4 text-[var(--text-muted)]" />
+        <h2 className="text-xs font-bold text-[var(--text-muted)] uppercase tracking-wider font-mono">Related Knowledge</h2>
+      </div>
+      <div className="grid grid-cols-1 sm:grid-cols-2 gap-3">
+        {related.map((r) => {
+          const rInfo = getSectionMeta(r.section);
+          return (
+            <Link
+              key={r.slug}
+              href={`/${r.slug}`}
+              className="group block bg-[var(--bg-surface)] hover:bg-[var(--bg-surface-hover)] border border-[var(--border-color)] hover:border-[var(--text-muted)] rounded-lg p-4 transition-colors shadow-xs"
+            >
+              <div className="flex items-center justify-between gap-2 mb-1.5">
+                <span className="text-[10px] text-[var(--text-muted)] font-mono uppercase font-semibold">
+                  {rInfo.icon} {r.section}
+                </span>
+                <time className="text-[11px] text-[var(--text-dim)] font-mono">
+                  {new Date(r.updatedAt).toLocaleDateString(undefined, { month: "short", day: "numeric" })}
+                </time>
+              </div>
+              <h3 className="text-xs sm:text-sm font-semibold text-[var(--text-primary)] group-hover:underline line-clamp-1">{r.title}</h3>
+            </Link>
+          );
+        })}
+      </div>
+    </aside>
+  );
+}