Function fetch_article_text 

pub async fn fetch_article_text(
    client: &Client,
    article_url: &str,
) -> Result<String>

What: Fetch one article through a caller-provided client and extract its text.

Inputs:

• client: Caller-configured reqwest client controlling transport policy.
• article_url: Absolute HTTP(S) article URL to fetch and use as link base.

Output:

• Extracted bounded article text or a transport, status, validation, or extraction error.

Details:

• The caller owns timeouts, redirects, proxy policy, and fetch cadence.
• The response body is read incrementally and rejected above MAX_ARTICLE_HTML_BYTES.

Errors

Returns an error for invalid URLs, failed requests, non-success responses, oversized bodies, invalid UTF-8, or extraction failures.