db_schema: Consider making test status an integer

We need a simple way for selecting and grouping tests based on status, and strings don't help with sorting. At the moment the Grafana dashboard prototype has to convert strings to numbers before doing any operations and that not likely to be efficient.

Consider switching the tests status in the database schema to numbers and converting on submission/querying.

Start by locating the database schema and the paths that submit and query test status values; the issue does not name specific files or tests. Determine the numeric status mapping and the affected Grafana dashboard operations, then verify that selection and grouping work without converting status strings.

Written by the indexing model from the issue text.