feat(market): add CoinGecko market data panel with cached /api/market endpoint

lib/api/url.ts

@@ -0,0 +1,9 @@
+export function buildApiUrl(path: string): string {
+  const base = process.env.NEXT_PUBLIC_API_BASE_URL?.trim();
+
+  if (!base) {
+    return path;
+  }
+
+  return `${base.replace(/\/$/, "")}${path}`;
+}