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

lib/server/market-cache.ts

@@ -0,0 +1,80 @@
+import { fetchCryptoMarketSnapshot } from "@/lib/api/crypto";
+
+export interface CachedCryptoMarketSnapshot {
+  code: string;
+  name: string;
+  priceUsd: number;
+  change24hPct: number | null;
+  marketCapUsd: number | null;
+  volume24hUsd: number | null;
+  updatedAt: string;
+  source: "CoinGecko";
+}
+
+interface CacheEntry {
+  data: CachedCryptoMarketSnapshot;
+  timestamp: number;
+}
+
+const CACHE_TTL_MS = 60_000;
+export const MARKET_CACHE_CONTROL_VALUE =
+  "s-maxage=60, stale-while-revalidate=600";
+
+const marketCache = new Map<string, CacheEntry>();
+const inFlightRequests = new Map<string, Promise<CachedCryptoMarketSnapshot>>();
+
+export async function getCryptoMarketWithCache(params: {
+  code: string;
+  name: string;
+  providerId: string;
+}): Promise<CachedCryptoMarketSnapshot> {
+  const cacheKey = params.code;
+  const cached = marketCache.get(cacheKey);
+  const now = Date.now();
+
+  if (cached && now - cached.timestamp < CACHE_TTL_MS) {
+    return cached.data;
+  }
+
+  const pending = inFlightRequests.get(cacheKey);
+
+  if (pending) {
+    return pending;
+  }
+
+  const requestPromise = (async () => {
+    const snapshot = await fetchCryptoMarketSnapshot(params.providerId);
+
+    const normalized: CachedCryptoMarketSnapshot = {
+      code: params.code,
+      name: params.name,
+      priceUsd: snapshot.priceUsd,
+      change24hPct: snapshot.change24hPct,
+      marketCapUsd: snapshot.marketCapUsd,
+      volume24hUsd: snapshot.volume24hUsd,
+      updatedAt: snapshot.updatedAt,
+      source: "CoinGecko",
+    };
+
+    marketCache.set(cacheKey, {
+      data: normalized,
+      timestamp: Date.now(),
+    });
+
+    return normalized;
+  })();
+
+  inFlightRequests.set(cacheKey, requestPromise);
+
+  try {
+    return await requestPromise;
+  } finally {
+    inFlightRequests.delete(cacheKey);
+  }
+}
+
+export function getLastCachedCryptoMarket(
+  code: string,
+): CachedCryptoMarketSnapshot | null {
+  return marketCache.get(code)?.data ?? null;
+}