Add migration to backfill models-by-engine-quantization index

[yuranich]

Summary

One-off migration script to backfill the compound models-by-engine-quantization index added in PR #145. HyperDB writes index keys at insert time; records inserted before the new index existed have no keys for it. Autobase does not replay the full log on restart, so a plain server restart leaves the new index empty for existing data.

Technical approach

The script opens the same Autobase/corestore used by the indexer (server must be stopped) and re-appends every model as a put-model dispatch with a custom apply handler that calls HyperDB.insert() with force: true. This bypasses the identical-value short-circuit so all index keys — including the new compound one — are written. Existing index keys are idempotently overwritten; the only net change is the new models-by-engine-quantization entries.

Usage

cd packages/qvac-lib-registry-server
node migrations/001-backfill-engine-quantization-index.js --storage <corestore-path> [--bootstrap <key>] [--dry-run] [--batch-size 50]

1. Stop the staging server
2. Deploy code with PR feat(qvac-registry-schema): add findBy() method to RegistryDatabase #145 merged and spec rebuilt
3. Run the migration
4. Restart the server

--dry-run lists all models without writing.

Breaking changes

None. One-off script, no runtime code modified.