The four endpoint routes and the 5-minute discovery sweep each read
custom-model-hosts.json, changed their copy and wrote it back through one
shared temp file name. Two of them at once could tear the file or drop each
other's record: ten creates sent together did not all land.
Every write now goes through mutateCustomModelHosts() (one promise chain, a
random temp name, mode 0600), with each check inside the same step as its
write. A file that does not parse is refused with 409 and never replaced.
A delete of an unknown id no longer rewrites the file. A guard test fails
any other writer in src/.
The id `local-ollama` is reserved for the model Codeman runs on this Mac: a
new endpoint may not take it, and while the record is the managed one it is
not edited, deleted or re-discovered from these routes.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
