The Docs Testing workflow has been the top CI flake source on master
(61 failures in the last 2 weeks), and almost every one fails with the
same signature:
Cause: [remark-localize-badges] Failed to download badge:
https://img.shields.io/badge/slack-join-orange.svg
Error: fetch failed
Build cannot continue with broken badges.
`remark-localize-badges` already retries 3× with backoff and a 30s
timeout. When shields.io rate-limits the CI runner anyway (very common
from GitHub Actions IP ranges), the plugin currently throws and the
entire docs build dies — even though the badge URL is fine and the
docs would render correctly via the remote URL.
Change the terminal failure path to log a warning and fall back to the
original remote URL. The rendered docs still show the badge (just
unlocalized for this build); the docs build keeps going. Add a
`REMARK_BADGES_STRICT=true` env var as an opt-in for the old
fail-the-build behavior, in case a release pipeline wants to catch
genuinely broken badge URLs.
