A mirror download cut off carries on from where it got to, and is tried again

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -37,6 +37,10 @@ APIs change between minors without a deprecation period.
   against the mirror's checksum, 195 GB on one core for eight minutes, while the replica still read "fetching 100%".
   It now checks four at once and says so: `checking 40% of 195 GB` in `ctl replicas`, "Checking the weights" in the
   chat page; and a check that takes long is not taken for a stuck download.
+- **A mirror download the registry cut off started again from nothing, or not at all.** Hugging Face's CDN ended a
+  60 GB transfer at 23 GB (`stream error … CANCEL`), the mirror deleted what had arrived, and `ctl model serve`
+  failed. The mirror now tries again up to six times, carrying on from where it got to (`Range`), keeps what arrived
+  when it gives up, and carries on from it after a restart too.
 
 ## v0.16.1 — 2026-10-30