frontend: scaffold Vite + React 19 + TS + Tailwind v4 + TanStack Query

Bare-minimum SPA that wires up to the FastAPI backend:

- Vite 6 + React 19 + TS strict, alias @/* to src/*
- Tailwind v4 via @tailwindcss/vite (no postcss)
- TanStack Query v5 with sane defaults (30s staleTime, no auto-refetch)
- React Router 7 for routing
- ECharts + Recharts available (charts land in Phase 1a)
- Vitest + @testing-library/react for tests
- Dev proxy /api → http://localhost:8080 (FastAPI)

Pages:
- Dashboard — pulls /networth, shows total + per-account cards.
  No chart yet (Phase 1a). Empty/error states for "no data" cases
  point users to the ingest CLI.

Header shows live API health (queue depth from /healthz). 274 KB JS
gzipped to 87 KB. typecheck + build pass.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/pages/Dashboard.tsx

@@ -0,0 +1,75 @@
+/**
+ * Dashboard — landing page. Wire up gets fleshed out in Phase 1a.
+ * For now: confirm we can reach /networth and render today's NW.
+ */
+import { useQuery } from '@tanstack/react-query';
+
+import { api } from '@/api/client';
+import { gbp } from '@/lib/format';
+
+export function Dashboard() {
+  const nw = useQuery({ queryKey: ['networth', 'current'], queryFn: api.networth.current });
+
+  if (nw.isLoading) {
+    return <p className="text-slate-500">Loading net worth…</p>;
+  }
+
+  if (nw.isError) {
+    return (
+      <div className="rounded-md border border-amber-200 bg-amber-50 p-4 text-amber-800">
+        <p className="font-medium">Couldn&apos;t reach the API.</p>
+        <p className="text-sm mt-1">
+          Make sure FastAPI is running on :8080 and Wealthfolio ingest has populated
+          <code className="px-1">account_snapshot</code>.
+        </p>
+      </div>
+    );
+  }
+
+  const data = nw.data!;
+  if (data.accounts.length === 0) {
+    return (
+      <div className="rounded-md border border-slate-200 bg-white p-6">
+        <p className="font-medium">No snapshots yet.</p>
+        <p className="text-sm text-slate-500 mt-1">
+          Run <code className="px-1">python -m fire_planner ingest</code> to pull from the
+          wealthfolio_sync mirror.
+        </p>
+      </div>
+    );
+  }
+
+  return (
+    <section className="space-y-6">
+      <header>
+        <h1 className="text-3xl font-semibold tracking-tight">Net worth</h1>
+        <p className="text-sm text-slate-500">As of {data.snapshot_date}</p>
+      </header>
+      <div className="rounded-lg border border-slate-200 bg-white p-6">
+        <div className="text-4xl font-semibold tabular-nums">{gbp(data.total_gbp)}</div>
+        <p className="text-sm text-slate-500 mt-1">{data.accounts.length} accounts</p>
+      </div>
+      <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-4">
+        {data.accounts.map((a) => (
+          <div
+            key={a.account_id}
+            className="rounded-lg border border-slate-200 bg-white p-4 flex flex-col gap-1"
+          >
+            <div className="flex items-center justify-between">
+              <span className="font-medium truncate">{a.account_name}</span>
+              <span className="text-xs uppercase tracking-wide text-slate-500">
+                {a.account_type}
+              </span>
+            </div>
+            <div className="text-2xl font-semibold tabular-nums">{gbp(a.market_value_gbp)}</div>
+            {a.currency !== 'GBP' && (
+              <div className="text-xs text-slate-500">
+                {gbp(a.market_value, true)} {a.currency}
+              </div>
+            )}
+          </div>
+        ))}
+      </div>
+    </section>
+  );
+}