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/lib/api.ts

@@ -0,0 +1,77 @@
+import type { Document, DocumentMeta, SectionInfo } from "@mcpedia/types";
+import { fetcher } from "./fetcher";
+
+export interface SearchApiHit {
+  slug: string;
+  title: string;
+  section: string;
+  score: number;
+  snippet: string;
+}
+
+export interface SearchApiResponse {
+  results: SearchApiHit[];
+  error?: string;
+}
+
+export interface DocsApiResponse {
+  docs?: DocumentMeta[];
+  error?: string;
+}
+
+export interface SectionsApiResponse extends Array<SectionInfo> {}
+
+export interface SingleDocResponse {
+  doc: Document;
+}
+
+export interface RelatedResponse {
+  results: DocumentMeta[];
+}
+
+export interface RevisionsResponse {
+  revisions: { id: string; slug: string; revisionNo: number; title: string; reason: string; createdAt: string; bodyLength: number }[];
+}
+
+export interface QueueStatusResponse {
+  waiting: number;
+  active: number;
+  completed: number;
+  failed: number;
+  delayed: number;
+}
+
+export interface TagsResponse {
+  tags: { tag: string; count: number }[];
+}
+
+export function docsUrl(section?: string, status = "published"): string {
+  const p = new URLSearchParams();
+  if (section) p.set("section", section);
+  if (status) p.set("status", status);
+  const qs = p.toString();
+  return qs ? `/api/docs?${qs}` : "/api/docs";
+}
+
+export function searchUrl(q: string, mode = "hybrid", limit = 30): string {
+  return `/api/search?q=${encodeURIComponent(q)}&mode=${mode}&limit=${limit}`;
+}
+
+export type FetchDocs = () => Promise<DocumentMeta[]>;
+export const fetchDocs: FetchDocs = async () => {
+  const data = await fetcher<DocsApiResponse | DocumentMeta[]>("/api/docs");
+  if (Array.isArray(data)) return data;
+  return data.docs ?? [];
+};
+
+export const fetchSections = () => fetcher<SectionInfo[]>("/api/sections");
+export const fetchSearch = (q: string, mode = "hybrid", limit = 30) =>
+  fetcher<SearchApiResponse>(searchUrl(q, mode, limit));
+export const fetchRelated = (slug: string, limit = 5) =>
+  fetcher<RelatedResponse>(`/api/related?slug=${encodeURIComponent(slug)}&limit=${limit}`);
+export const fetchRevisions = (slug: string, limit = 20) =>
+  fetcher<RevisionsResponse>(`/api/revisions?slug=${encodeURIComponent(slug)}&limit=${limit}`);
+export const fetchSingleDoc = (slug: string) =>
+  fetcher<SingleDocResponse>(`/api/docs/${encodeURIComponent(slug)}`);
+export const fetchQueueStatus = () => fetcher<QueueStatusResponse>("/api/queue/status");
+export const fetchTags = () => fetcher<TagsResponse>("/api/tags");

apps/web/app/lib/fetcher.ts

@@ -0,0 +1,32 @@
+export class FetchError extends Error {
+  status: number;
+  info: unknown;
+  constructor(message: string, status: number, info: unknown) {
+    super(message);
+    this.name = "FetchError";
+    this.status = status;
+    this.info = info;
+  }
+}
+
+export async function fetcher<T>(url: string): Promise<T> {
+  const res = await fetch(url);
+  if (!res.ok) {
+    let info: unknown = null;
+    try {
+      info = await res.json();
+    } catch {
+      try {
+        info = await res.text();
+      } catch {
+        info = null;
+      }
+    }
+    const msg =
+      (info as { error?: string })?.error ||
+      (typeof info === "string" ? info : null) ||
+      `Request failed: ${res.status} ${res.statusText}`;
+    throw new FetchError(msg, res.status, info);
+  }
+  return (await res.json()) as T;
+}

apps/web/app/lib/swr.tsx

@@ -0,0 +1,19 @@
+"use client";
+
+import { SWRConfig } from "swr";
+
+export default function SWRProvider({ children }: { children: React.ReactNode }) {
+  return (
+    <SWRConfig
+      value={{
+        dedupingInterval: 4_000,
+        focusThrottleInterval: 10_000,
+        revalidateOnFocus: true,
+        shouldRetryOnError: false,
+        errorRetryCount: 0,
+      }}
+    >
+      {children}
+    </SWRConfig>
+  );
+}