Description:
Audit the Ruby driver and Mongoid codebases for dead code, including private methods that are never called, unreachable branches, and obsolete helpers. Remove or refactor these sites to simplify the codebase, reduce maintenance surface area, and make future refactors easier. Where removal isn’t obvious, add comments or small tests to clarify intent.

Acceptance Criteria:

• Tooling (e.g. coverage, grep, IDE analysis) identifies a concrete list of dead/unreachable code sites.
• Each site is either removed, refactored to be used, or explicitly documented as intentionally unused.
• CI is green and there are no new RuboCop or coverage regressions from the changes.