feat: enhance README and improve product data handling in cache, llm, reader, and writer modules

src/cache.ts

@@ -12,11 +12,20 @@ export async function connectCache(): Promise<void> {
       maxRetriesPerRequest: 1,
       connectTimeout: 3000,
       lazyConnect: true,
+      retryStrategy: () => null,
+      reconnectOnError: () => false,
+    });
+    // Swallow connection-level errors after we intentionally disable cache.
+    redis.on("error", () => {
+      // no-op
     });
     await redis.connect();
     console.log("Redis connected");
   } catch (err) {
     console.warn(`Redis unavailable, running without cache: ${err}`);
+    if (redis) {
+      redis.disconnect();
+    }
     redis = null;
     disabled = true;
   }
@@ -32,10 +41,18 @@ export async function getCache(asin: string): Promise<EnrichedProduct | null> {
   }
 }
 
-export async function setCache(asin: string, data: EnrichedProduct): Promise<void> {
+export async function setCache(
+  asin: string,
+  data: EnrichedProduct,
+): Promise<void> {
   if (!redis) return;
   try {
-    await redis.set(`asin:${asin}`, JSON.stringify(data), "EX", config.cacheTtl);
+    await redis.set(
+      `asin:${asin}`,
+      JSON.stringify(data),
+      "EX",
+      config.cacheTtl,
+    );
   } catch {
     // Non-critical, continue without caching
   }