v0.1.3 — MySQL role migration and writes

MySQL installations can now migrate and synchronize roles. The stored system flag is a reserved MySQL identifier; unquoted migration and write statements previously failed with a SQL syntax error. The migration and repository now quote that fixed column using the PDO driver's identifier syntax.

The column name, role data and grant rules remain unchanged. Existing installations require no schema change. Coverage includes the SQLite policy suite and a real MySQL 8.4 migration/create/delete/sync regression, now run in CI. Local PHP 8.5.10 passed 50 tests with 79 assertions, formatting and strict Composer validation; main CI passed for the tagged merge commit.