Description:
Audit the Ruby driver for structural antipatterns that make the code brittle or surprising, such as Mongo::Cluster.create mutating its argument via instance_variable_set, and other uses of instance_variable_set or similar meta-programming shortcuts. Replace these with clearer, encapsulated designs (e.g., proper initializers, explicit accessors, small helper objects) that preserve behavior while improving maintainability and testability.

Acceptance Criteria:

• All uses of instance_variable_set and similar meta-programming APIs in the driver are cataloged.
• For each site, either:
  • The pattern is replaced with a clearer, encapsulated alternative, or
  • It is explicitly documented and constrained (e.g., a single well-justified internal helper).
• No behavior regressions in CI, and code in Mongo::Cluster (and other core types) reads as straightforward OO Ruby.