NotImplemented error while running in windows.

## The problem

On Windows, running a scrapegraphai scraper (SmartScraperGraph or SearchGraph) crashes with an Uncaught app exception ending in NotImplementedError. The underlying cause is asyncio: Windows defaults to the Proactor event loop, which scrapegraphai does not handle.

## The fix

Windows uses the Proactor event loop, which breaks the asyncio usage in scrapegraphai. Notebook users confirmed the fix is to apply nest_asyncio before running:

import nest_asyncio
nest_asyncio.apply()

Put this at the top of your notebook or script before creating the scraper graph. This applies to SmartScraperGraph and SearchGraph alike; the underlying cause is the same asyncio-on-Windows issue.