Add new streaming capability to the MemoryAdaptiveDispatcher and AsyncWebCrawler
to allow processing URLs with real-time result streaming. This enables
processing results as they become available rather than waiting for all
URLs to complete.
Key changes:
- Add run_urls_stream method to MemoryAdaptiveDispatcher
- Update AsyncWebCrawler.arun_many to support streaming mode
- Add result queue for better result handling
- Improve type hints and documentation
BREAKING CHANGE: The return type of arun_many now depends on the 'stream'
parameter, returning either List[CrawlResult] or AsyncGenerator[CrawlResult, None]
