X_CATALOG_UNREGISTERED
Means
a shipped catalog never reached the runtime registry
Typical cause
defineCatalogs() in a module the boot scan never imports, or one that throws on import — every string renders ⟦key⟧ while x verify is green. When two copies of @ultimat3/i18n are installed the cause says so instead, and the fix is the install's (X_PACKAGE_DUPLICATED, reported beside it): the call is where it should be and registered into the copy the CLI does not read
Fix
move the defineCatalogs() call into packages/i18n/src/index.ts and read strings through its useT(); x i18n check --json re-checks