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/Sidebar.tsx

@@ -1,9 +1,10 @@
 "use client";
 
-import { useEffect, useState, useMemo } from "react";
+import { useState, useMemo } from "react";
 import Link from "next/link";
 import { usePathname } from "next/navigation";
 import { getSectionMeta } from "@mcpedia/config/sections";
+import { useDocuments } from "@/hooks/useDocuments";
 import {
   Folder,
   FolderOpen,
@@ -14,6 +15,8 @@ import {
   Plus,
 } from "lucide-react";
 
+import type { DocumentMeta } from "@mcpedia/types";
+
 interface Doc {
   slug: string;
   title: string;
@@ -182,21 +185,11 @@ function TreeNodeItem({
 }
 
 export default function Sidebar() {
-  const [docs, setDocs] = useState<Doc[]>([]);
+  const { docs } = useDocuments();
   const [filterText, setFilterText] = useState("");
   const [collapsedMap, setCollapsedMap] = useState<Record<string, boolean>>({});
   const pathname = usePathname();
 
-  useEffect(() => {
-    fetch("/api/docs")
-      .then((r) => r.json())
-      .then((data) => {
-        if (Array.isArray(data)) setDocs(data);
-        else if (data?.docs) setDocs(data.docs);
-      })
-      .catch(() => setDocs([]));
-  }, []);
-
   function toggleCollapse(slug: string) {
     setCollapsedMap((prev) => ({ ...prev, [slug]: !prev[slug] }));
   }
@@ -208,7 +201,7 @@ export default function Sidebar() {
       (d) =>
         d.title.toLowerCase().includes(lower) ||
         d.slug.toLowerCase().includes(lower) ||
-        d.tags.some((t) => t.toLowerCase().includes(lower)),
+        d.tags.some((t: string) => t.toLowerCase().includes(lower)),
     );
   }, [docs, filterText]);