keepRows
open fun keepRows(@NonNull db: SQLiteDatabase, @NonNull dbName: String, oldVersion: Int, newVersion: Int, @NonNull createSqls: Array<String>)
Migrate every table of a DB without losing rows, for helpers whose own code cannot work with a table left in an older shape. For each CREATE statement: reconcileColumns; if that FAILED (or could not even read the table), the old table is renamed to <name>__kept_v<oldVersion> (its rows stay in the DB file, nothing is deleted) so the helper's onCreate can create a working table in its place. The caller runs onCreate after.