Bugfix unstable database order

[Louwrensth]

Summary

This PR fixes unstable pagination in the database layer (src/simdb/database/database.py) by making simulation listing order deterministic.

Changes

• Make database pagination use a stable, deterministic sort order.
• Raise DatabaseError when an unknown sort column is requested.
• Update the database test fixture to simulate unordered query results by rotating rows on each Query.all() call.
• Add regression coverage to show duplicate entries in query pagination (limit) when no stable sort is applied.

Validation

• 24 passed in tests/database/test_metadata_queries.py