Resolve which schemas a file-emit pass should rebuild.
--skipdb and dirtySchemaOnly === false rebuild every schema (write-if-changed
still keeps mtimes stable). Otherwise only schemas that contain a new/modified
entity are dirty — missing files are added later by schemasToEmit.
Resolve which schemas a file-emit pass should rebuild.
--skipdbanddirtySchemaOnly === falserebuild every schema (write-if-changed still keeps mtimes stable). Otherwise only schemas that contain a new/modified entity are dirty — missing files are added later by schemasToEmit.