### What problem does this PR solve?
Closes#14865
`download_img` in `common/misc_utils.py` is used for OAuth avatar URLs.
The previous implementation called `async_request` from
`common.http_client`, which followed redirects without re-validating
each hop and did not apply the same SSRF protections as this path needs.
That made it possible to reach non-public or disallowed targets (for
example via redirects or unsafe URLs) when fetching avatars.
This change replaces that flow with an explicit, bounded fetch: each URL
(including every redirect target) is checked with
`common.ssrf_guard.assert_url_is_safe`, DNS is pinned with
`pin_dns_global`, `httpx` streams the body with `follow_redirects=False`
and a manual redirect loop (capped by
`RAGFLOW_OAUTH_AVATAR_MAX_REDIRECTS`), and total response size is capped
(`RAGFLOW_OAUTH_AVATAR_MAX_BYTES`). Timeouts, proxy, and user agent
align with `HTTP_CLIENT_*` env vars without importing `http_client`, so
lightweight tests stay simple.
Unit tests cover empty/None URLs, loopback, cloud metadata-style
addresses, and disallowed schemes so SSRF regressions are caught early.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
---------
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
### What problem does this PR solve?
Fixed thread pool workers and improve retrieval component
### Type of change
- [x] Refactoring
- [x] Performance Improvement
### What problem does this PR solve?
Only support MinerU-API now, still need to complete frontend for
pipeline to allow the configuration of MinerU options.
### Type of change
- [x] Refactoring
### What problem does this PR solve?
Rename function and refactor log message
### Type of change
- [x] Refactoring
Signed-off-by: Jin Hai <haijin.chn@gmail.com>
### What problem does this PR solve?
Feat: add mineru auto installer
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Add get_uuid, download_img and hash_str2int into misc_utils.py
### Type of change
- [x] Refactoring
---------
Signed-off-by: Jin Hai <haijin.chn@gmail.com>
