v2.0.9 — failed SQLite-open shutdown repair

Fixes C5-R1: failed SQLite storage opens now wait for their worker to terminate before returning the database error. Cleanup is bounded and preserves the original error cause. Read-only enforcement, successful opens and trading/transfer boundaries are unchanged.

The repair includes deterministic real-worker regressions, independent review and four caught mutations. Windows and installed Linux suites, static checks and supported aiosqlite lifecycle checks passed for the repair. Final release CI and image identity are recorded in the roadmap after publication.

For operators upgrading from 2.0.7, this also includes the 2.0.8 stabilization changes. Follow the upgrade/rollback handoff and 2.0.x limitations. Publication and deployment do not constitute formal phase acceptance.

See the repair evidence and current roadmap receipts.