INJ-01 (high): fetch_image_block used follow_redirects=True with no per-hop
revalidation and discarded the resolved-IP pin, so an attacker-authored Slack/
Linear image URL could 302-redirect the fetch to an internal host / cloud
metadata endpoint (blind SSRF), and DNS-rebinding could bypass the one-shot
is_url_safe check. Route image fetches through the same per-hop resolve+pin+
revalidate loop the http_request tool uses, lifted into url_safety as the shared
request_with_safe_redirects. Also strip the per-host Slack/Linear bearer token
on redirect so it can't be replayed to a redirect target.
SC-1 (low): linear.py logged full image URLs (which can carry signed tokens) at
DEBUG; multimodal logged them at INFO on every fetch. Log host-only.
Sink lived in multimodal.py (unchanged by the feature work) but PR #128 widened
its reach by no longer dropping images for text-only models. Fixing on the base
branch so #130/#129 inherit it on rebase. Adds fetch_image_block SSRF regression
tests (redirect-to-internal blocked; auth stripped on redirect).