`SET STORAGE DEFAULT` needs PostgreSQL 16, but the official docker
images pin `postgres:15`, so migration 0156 failed on those
deployments. The migration now uses `SET STORAGE EXTENDED`, the
storage mode of the type of every column it touches (text, text[],
jsonb and bytea), which leaves the catalog in the same state on any
supported version.
The documented PostgreSQL floor goes back to >=15, the reason for
raising it was that syntax.
Verified on the test database: the 62 columns reset and no table
column keeps the legacy EXTERNAL storage.
The backend memory now records that migrations must stay within
PostgreSQL 15 syntax.
AI-assisted-by: minimax-m3.1-flash-free
021492a577