refactor: add shared cookie utility to core package

Move cookie parsing logic to a dedicated utility module that can be
shared across all scrapers. Supports both JSON array and cookie string
formats for all input sources (parameter, env var, file).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/core/src/index.ts

@@ -36,7 +36,8 @@ export {
 } from "./scrapers/kijiji";
 // Export shared types
 export * from "./types/common";
+// Export shared utilities
+export * from "./utils/cookies";
 export * from "./utils/delay";
 export * from "./utils/format";
-// Export shared utilities
 export * from "./utils/http";