Function resolveFromVersion

resolveFromVersion(
    stored: string,
    current: string,
    worldHasContent: boolean,
): string
Resolve the effective "from" version for a world, distinguishing a brand-new world from a pre-tracking legacy one.

The systemMigrationVersion setting defaults to "" for both a freshly created world (nothing to migrate) and a world created before migration tracking existed (everything to migrate). They are told apart by whether the world holds any content:
- stored version present → use it verbatim.
- empty + world unpopulated → fresh: return current, so the plan is empty and the runner simply stamps the version forward.
- empty + world populated → legacy: return "0.0.0", so every registered migration runs.
Parameters
- stored: string
  The stored systemMigrationVersion (may be empty).
- current: string
  The running system version.
- worldHasContent: boolean
  Whether the world holds any migratable documents.
Returns string
The version to plan migrations from.
- Defined in src/entity/migration/MigrationRegistry.ts:185