- storage/db_pg.py: thin psycopg2 connection shim (?->%s translation,
autocommit, .df(), and per-test isolated schema for ':memory:').
- storage/db.py: delegate get_connection/get_memory_connection to db_pg.
- storage/pg_schema.sql: Postgres schema, applied on connect.
- research/query.py runs UNMODIFIED on Postgres via the shim.
- ingestion upserts: INSERT OR REPLACE -> INSERT ... ON CONFLICT DO UPDATE.
- event_store: drop invalid btree-on-JSON-text index.
Full logic suite: 67/67 green against Postgres (was DuckDB).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
