sfdupes is pre-1.0, with no installed base and no databases anywhere,
so the schema is changed in place and its version stays 1.
schemaVersion goes back to 1; the six-column files table, content
included, is the version 1 schema. The check that stops on a database
with any other version stays. README.md and TODO.md no longer describe
a version 2 or rejecting and rescanning version 1 databases. The
main.go package comment still described 1024-byte end windows and said
full file contents are never read; it now describes the hashes the
code computes.
Model: opus-5-5