IMPORTANT: While I tested this migration a few times and read through things as carefully as I could, making changes to C++ codebase and SQLite store can be risky. Adding @ashoat and @kamil as blocking to take a look... would appreciate careful review to ensure everything is correct.
In this diff we:
1. Remove `lastPruned`/`lastNavigatedTo` from `MessageStoreThread` struct and remove usages on C++ side.
2. Introduce SQLite migration that drops `lastPruned` and `lastNavigatedTo` columns.
As of D9475, we've started ignoring what's persisted here in SQLite entirely... so this is effectively just dead code that we're cleaning up.
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Depends on
D9475