Real-app runtime observations

Base c90b67859a6d85fc957f9ffe25ba95113c6479d3
The restarted server logged 5 occurrences of:
ProviderAdapterProtocolError: pi provider protocol error: Pi session has no registered thread.
The browser displayed the rollback failure and retained turn two.

Head ac86d38d4e2d7fdc76922fce7eefd6fe7f56a925
After restart, the browser removed turn two and restored its prompt to the composer.
The follow-up asking only about retained conversation history returned one.txt.

Both used fresh, separate databases and Git projects. Provider sessions were real Pi sessions.
AI-assisted; verified with the tests and tools listed above.