[Bug]: Allow configuration of `link_preview_timeout` in `AdaptiveCrawler`

[blghtr]

crawl4ai version

0.7.7

Expected Behavior

When using AdaptiveCrawler, I expect to be able to configure the timeout for the internal link preview extraction step. This should likely be possible via the AdaptiveConfig object or a parameter in AdaptiveCrawler.__init__, ensuring that CrawlerRunConfig within _crawl_with_preview respects this custom timeout.
This issue prevents effective adaptive crawling on sites with high latency or complex DOMs that take longer than 5s to reach a state where the head metadata is available for relevance scoring.

Current Behavior

In AdaptiveCrawler._crawl_with_preview, the CrawlerRunConfig for the preview step uses a hardcoded timeout of 5 seconds. This value cannot be overridden by any public configuration API.

Relevant code in adaptive_crawler.py (lines 1454-1467):

        config = CrawlerRunConfig(
            link_preview_config=LinkPreviewConfig(
                # ...
                timeout=5,  # <--- HARDCODED
                # ...
            ),
            # ...
        )

Is this reproducible?

Yes

Inputs Causing the Bug

- **Target URL**: Any slow-loading website (response time > 5s or heavy JS rendering).
- **Config**: Standard `AdaptiveConfig`.

Steps to Reproduce

1. Initialize `AdaptiveCrawler` with standard configuration.
2. Call `await crawler.digest(url="https://slow-website.example.com", query="test")`.
3. Observe that the crawler likely fails to extract link contexts or returns incomplete results because the preview step times out after 5 seconds, regardless of any other timeout settings.

Code snippets

OS

Windows 11

Python version

3.11

Browser

No response

Browser version

No response

Error logs & Screenshots (if applicable)

No response