fix(media): raise ToolError on redirect response missing Location header

[Preciousuche]

Description

closes #616
``### Summary
Fixes _fetch_image_url crashing with `httpx.StreamClosed` when a redirect response omits the `Location` header, and adds test coverage for redirect handling.

Problem

When receiving a redirect status code (301, 302, 303, 307, 308) missing a Location header, _fetch_image_url closed the response (await resp.aclose()) and breaked out of the redirect loop. Downstream, resp.raise_for_status() does not raise on 3xx, leading into async for chunk in resp.aiter_bytes() on the closed stream. This failed with an internal StreamClosed error rather than a clear explanation.

Solution

• When location is missing on a redirect response, immediately raise an explicit ToolError naming the status code, the current URL, and the missing header.
• Added comprehensive unit tests in tests/test_tools/test_media_image_download_cap.py:
  • Missing Location header raises clear ToolError.
  • Valid Location header is followed and the image downloaded.
  • Exceeding _MAX_REDIRECTS raises ToolError("Too many redirects (>5)").

Fixes #616

[andreapn]

Closing as superseded. Reviewed alongside the other three PRs on issue #616; #773 was picked.

Your fix is correct and your tests are good — this was a close call. #773 edged it on test coverage (all five 3xx codes parametrized, a mid-chain redirect asserting the failing hop is named rather than the URL the caller passed, and both sides of the _MAX_REDIRECTS boundary) and it carries a CHANGELOG entry.

Thanks for the contribution — nothing wrong with this one.