X_JOB_CONCURRENCY_UNENFORCEABLE
Means
job.concurrency is declared and cannot be enforced
Typical cause
a jobs driver with no lease store — the cap then holds per process and the fleet runs concurrency × replicas. job.concurrency was documented, in the manifest, and enforced by nothing; the worker now refuses to start rather than run with the wrong number, which is what axiom 3 means by a convention that is not a build error not existing
Fix
remove concurrency from the job cause names, or drop the jobs: field from apps/<app>/runtime.ts so the boot installs postgresJobDriver() over DATABASE_URL — the pg driver is the one with a lease store