The RDF engine has two stored object encodings: legacy null-separated numeric/date keys and the newer unit-separator form used by optional optimization paths. A local decoder in BaseQuintStore only understood part of that contract, so query projections could leak internal keys instead of RDF literals.

Constraint: The release line already shipped RDF3X/Postgres changes and needs a narrow patch before production data is reset.
Rejected: Add another local parser branch | this would duplicate serialization rules and drift again.
Confidence: high
Scope-risk: narrow
Directive: Keep object serialization/deserialization centralized in src/storage/quint/serialization.ts.
Tested: bun run check:platform-package-version
Tested: bun run build:ts
Tested: bun test tests/storage/quint/optional-optimization.test.ts tests/storage/quint/pglite-quint-store.test.ts tests/storage/rdf/PostgresRdfEngine.test.ts --runInBand
Tested: bun run build:components
Tested: bun run test:integration