applyOnlyOffice only ran the connection check when a setting changed, so
once it failed while settings matched, nothing checked again and the
failure was logged once and forgotten. The client now remembers whether
the last check failed and re-runs it on every tick until it passes;
index.ts logs every failing tick and one line when it recovers.
occ's config:app:set put the secret on the docker exec command line, so
it sat in the docker CLI's argv, the container's php argv and docker's
exec record. Apply jwt_secret through config:import on occ's stdin
instead; the other three onlyoffice keys still go through
config:app:set.