SLayer 0.9.8

This release adds an OSI importer and tidies up the Postgres facade.

Import OSI semantic models

You can now bring an existing Open Semantic Interchange (OSI) semantic model into SLayer with slayer import-osi <path> --datasource X.

Point it at a YAML/JSON file or a directory and it converts each OSI model into a SLayer model - saving them and printing a per-model conversion report, just like import-dbt. OSI maps straight onto SLayer's own concepts: raw-SQL metrics become colon-syntax measures, explicit relationships become joins, and column types and primary keys are read from the live database. Metrics that can't be represented cleanly are reported rather than silently mangled.

See the new OSI import guide for details.

Postgres facade fixes

Query errors now come back with proper SQLSTATE codes and clearer messages instead of being swallowed, and double-quoted identifiers in a WHERE clause (including schema-qualified ones) are correctly treated as column references. You can also enable opt-in per-stage query timing logs via an environment variable to diagnose slow queries.

Other fixes

Building an MCP server against a stubbed or metadata-only storage no longer crashes during construction - help-memory seeding is now skipped for non-backend storage and is best-effort otherwise.