Drops the .kb/kb.db migration path, legacy backup filename handling, and
backward-compat test suites. Renames internal kbDir identifiers to
fusionDir and hasKbProject/isValidKbProject to their fusion equivalents.
- Remove needsCentralMigration, autoMigrateToCentral, and the
"needs-migration" FirstRunState; checkAndMigrate and KB_SKIP_MIGRATION
env var are gone
- Remove LEGACY_BACKUP_DIR and canonicalizeBackupDir; listBackups no
longer matches kb-* filenames
- Delete backward-compat.test.ts and store-backward-compat.test.ts;
update remaining tests to new 3-state first-run model
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
f20d0b5a18