Manual transition package: current layout and schema

Standalone migration tools for existing V1 and pre-layout V2 installations. Download and extract transition-bundle.tar.gz outside your checkout, verify its SHA256 against transition-bundle.sha256, and read MIGRATING.md before running anything. Backups and explicit destructive-change acknowledgement are required. The bundle includes dry-run-first layout relocation and transactional database conversion; it never starts application workers. Legacy source and tests remain on legacy-transition, outside main. V1 is retired and preserved at v1-retired; pre-layout V2 is preserved at pre-layout-cleanup. New installations should use main and ./setup.sh.