Harden onion boot flow and deepen site surfaces

Add persistent onion key backup and restore, improve startup resilience, and flesh out the major site verticals with richer navigation, search coverage, and operator documentation.

Made-with: Cursor

app/market/layout.tsx

@@ -0,0 +1,5 @@
+import MarketSiteChrome from "@/components/market/MarketSiteChrome";
+
+export default function MarketLayout({ children }: { children: React.ReactNode }) {
+  return <MarketSiteChrome>{children}</MarketSiteChrome>;
+}