v0.68.0

What's Changed

• feat(adk): add ADK v2 session/memory/artifact parity and Postgres vector memory across psqlpy and adbc by @cofin in #852
• feat(postgres): add pooler_mode, direct_dsn session split, and AlloyDB columnar GUC across asyncpg, psycopg, and psqlpy by @cofin in #850
• feat(oracledb): add enterprise topology, session context hooks, streaming Arrow, HNSW/RRF, and 26ai capabilities by @cofin in #849
• feat(observability): add wire-level sqlcommenter, zero-RTT Oracle trace piggybacking, and DuckDB statement profiling by @cofin in #851
• chore(release): bump to v0.68.0 and update changelog by @cofin in #853

Full Changelog: v0.67.0...v0.68.0