GeezerVison

Duplicating a record in a WITHOUT ROWID table with a composite primary key
failed with "NOT NULL constraint failed", because the empty record only got
a key value for single column keys. Generate a key whose last column is
max+1 (other key columns get a neutral value) so the insert succeeds, and
return the composed sqlb_make_single_value identifier of the new row instead
of the plain number so the model can find the row again.

Columns covered by a UNIQUE constraint were copied into the new row, which
always violated the constraint, showed an "Error changing data" dialog and
left a half filled record. Like the primary key they are now not copied.

Add test-duplicate-record covering these and the existing cases.

It was removed in Qt6.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>