feat(mcpedia): Phase 1 MVP — monorepo, Core, Web UI, MCP server, Postgres FTS

- bun workspaces + Turborepo monorepo (apps/web, apps/mcp; packages/*, scripts)
- @mcpedia/core single business-logic layer (Document/Content/Search services)
- @mcpedia/db Drizzle schema: documents + weighted tsvector (GIN) for FTS
- @mcpedia/parser frontmatter, @mcpedia/search Postgres FTS (ts_rank+ts_headline)
- Next.js 16 Web UI (home/doc SSG, search dynamic) + react-markdown render
- MCP server (stdio) with 4 tools + in-memory smoke test
- scripts/indexer walks content/ -> upserts into Postgres
- 4 seed docs; README + PHASES status

apps/web/app/layout.tsx

@@ -0,0 +1,39 @@
+import type { Metadata } from "next";
+import Link from "next/link";
+import "./globals.css";
+
+export const metadata: Metadata = {
+  title: "MCPedia",
+  description: "Knowledge base for humans and AI agents via MCP.",
+};
+
+export default function RootLayout({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  return (
+    <html lang="en" className="h-full antialiased">
+      <body className="min-h-full flex flex-col bg-zinc-50 text-zinc-900 dark:bg-zinc-950 dark:text-zinc-100">
+        <header className="border-b border-zinc-200 dark:border-zinc-800">
+          <div className="mx-auto max-w-5xl px-4 py-3 flex items-center justify-between">
+            <Link href="/" className="font-semibold tracking-tight">
+              MCPedia
+            </Link>
+            <nav className="flex gap-4 text-sm">
+              <Link href="/" className="hover:underline">Home</Link>
+              <Link href="/search" className="hover:underline">Search</Link>
+              <Link
+                href="/docs"
+                className="hover:underline"
+              >
+                Docs
+              </Link>
+            </nav>
+          </div>
+        </header>
+        <main className="mx-auto max-w-5xl w-full flex-1 px-4 py-8">{children}</main>
+      </body>
+    </html>
+  );
+}