auto .env creation + API key validation

🚀 v0.2.0 – Auto .env + API Key Check

✨ Features

• Automatically copies .env.example → .env on first run
• Warns if SCRAPERAPI_KEY is missing or still a placeholder
• Moves all env setup logic into if __name__ == "__main__" for cleaner imports

🔧 Improvements

• Prepped for modular package structure and future PyPI support