Emit LIMIT -1 when offset is used without limit - #821

Fixes:

• rows_where() raises OperationalError when offset is given without limit #816.

SQLite requires a LIMIT clause to appear before OFFSET, so passing offset without limit generated invalid SQL:

db["t"].rows_where(offset=2)
# select * from "t" offset 2
# OperationalError: near "2": syntax error

A negative limit means "no upper bound" in SQLite, so emitting limit -1 offset N returns all rows from position N onwards.

The issue mentions rows_where() and search_sql(). There is a third instance of the same pattern in the sqlite-utils rows CLI command, which fails the same way:

$ sqlite-utils rows data.db t --offset 1
Error: near "1": syntax error

So this fixes three sites:

• Queryable.rows_where() — also covers pks_and_rows_where(), which delegates to it
• Table.search_sql() — also covers search()
• the sqlite-utils rows CLI command

Tests added:

• two new cases in the existing test_rows_where_offset_limit parametrize (offset with limit=None, including offset=0)
• test_pks_and_rows_where_offset_without_limit
• test_search_offset_without_limit
• a new --offset without --limit case in the sqlite-utils rows CLI parametrize

Full suite passes (1379 passed, 16 skipped), plus black --check, flake8 and mypy are clean.

📚 Documentation preview 📚: https://sqlite-utils--821.org.readthedocs.build/en/821/