Without a databaseBuilder, the Matrix SDK has no event storage. The
initial sync populates room metadata but timeline events are not
retained in any queryable form. room.getTimeline() returns empty.
Added MatrixSdkDatabase('m8chat_matrix') which uses IndexedDB on web
and SQLite on mobile via Hive. Events are now persisted and timeline
loads room history correctly.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>