The init container fetched a token once at pod start with a client_credentials grant
against a web app. A web app has no such grant, so the fetch could not work; and a
token fetched once is dead within the hour while the pod runs for weeks.
llm-token-vendor runs beside the app. It signs a machine-key assertion for the
paperless-llm service account, exchanges it for a token, and rewrites
/app/data/llm_token.txt atomically at 80% of the token lifetime. The vendor image
keeps using CUSTOM_API_KEY_FILE, so it needs no change and no OIDC support.
The key is re-read on every mint, so a rotation lands without a restart: publish the
new key, the next mint uses it, retire the old one.
paperless-llm is a separate service account from poimen-llm, so revoking one caller
leaves the other working.