fix: restore legacy store files to simple_store_opt baseline

These files were modified during early development on this branch but
those changes were superseded by the new global.rs/per_key.rs stores.
Reset to simple_store_opt versions so they don't appear as unintended
changes in the PR.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: zz_y