chore(template): clean-slate template snapshot from bb4a0c7

Curated, product-agnostic snapshot of the post-story-04 tree: demo
content deleted, auth-only reference feature, web-next shell, all gates
green. Product-specific docs, ADRs 027-029, PRDs/epics/archive, editor
library traces, and product naming are curated out; generic template
repairs (coverage provider devDeps, root test:coverage script, live
lint fixes, root-only release-please) are kept. See TEMPLATE.md for
provenance, curation list, and usage.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016j8z4VHjedXDTjEDNg7qHK

packages/core-trpc/src/providers/tanstack-provider.tsx

@@ -0,0 +1,30 @@
+"use client";
+
+import { useState } from "react";
+import { QueryClientProvider } from "@tanstack/react-query";
+import { createTRPCClient, httpBatchLink } from "@trpc/client";
+import superjson from "superjson";
+import type { AppRouter } from "@repo/core-api";
+import { TRPCProvider } from "../client";
+import { getQueryClient } from "../query-client";
+
+export function TanstackTrpcProvider({
+  children,
+  trpcUrl,
+}: {
+  children: React.ReactNode;
+  trpcUrl: string;
+}) {
+  const [queryClient] = useState(() => getQueryClient());
+  const [trpcClient] = useState(() =>
+    createTRPCClient<AppRouter>({
+      links: [httpBatchLink({ url: trpcUrl, transformer: superjson })],
+    }),
+  );
+
+  return (
+    <TRPCProvider trpcClient={trpcClient} queryClient={queryClient}>
+      <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+    </TRPCProvider>
+  );
+}