brevis-sql v0.7.0

Changed: the module is brevis.sh/brevis/sql

• go install brevis.sh/brevis/sql/cmd/brevis-sql@latest (and
  brevis-sql-api) from this release on; versions up to 0.6.0 stay under
  github.com/AreteAcademy/brevis/sql. It requires the SDK as
  brevis.sh/brevis/sdk v0.88.0.

Changed: the images are brevissh/brevis-sql and brevissh/brevis-sql-api

• This release publishes to docker.io/brevissh/*, not
  areteacademy/*, which keeps the versions already there. The current ones
  were copied over with the same digests.

Fixed: a failed table rebuild no longer drops the table

• On Postgres, the DROP and the CREATE TABLE AS of a table model (and of
  incremental --full-refresh) run in one transaction, so a failing CREATE
  leaves the old table readable. (A follow-up builds the new table aside and
  swaps it in by rename, so readers wait only for the rename.)

Added: lookback for incremental models

• An incremental model can set lookback: 2h (30m, 1d...): the filter is
  w >= max - lookback instead of w > max, so a row that ties the watermark or
  arrives late is merged instead of lost until a --full-refresh. Without it
  the SQL is byte-identical. The watermark must be a TIMESTAMP column.