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

lib/market.ts

@@ -0,0 +1,29 @@
+import { z } from "zod";
+
+export interface CryptoMarketResponse {
+  code: string;
+  name: string;
+  priceUsd: number;
+  change24hPct: number | null;
+  marketCapUsd: number | null;
+  volume24hUsd: number | null;
+  updatedAt: string;
+  source: string;
+}
+
+const marketResponseSchema = z.object({
+  code: z.string(),
+  name: z.string(),
+  priceUsd: z.number().positive(),
+  change24hPct: z.number().nullable(),
+  marketCapUsd: z.number().nullable(),
+  volume24hUsd: z.number().nullable(),
+  updatedAt: z.string(),
+  source: z.string(),
+});
+
+export function parseCryptoMarketResponse(
+  payload: unknown,
+): CryptoMarketResponse {
+  return marketResponseSchema.parse(payload);
+}