JavaScript tests need to distinguish the last stable FCV from the latest FCV while releases are developed from master. The current shell FCV values are defined in the FCV helper, and the global test bindings make them available to tests, but there is no explicit representation of the last stable FCV.

Expose a distinct last-stable FCV value through the test-facing shell API and source it from the server’s release metadata. This will let tests and test suites select the FCV supported by the latest released branch without hardcoding or inferring it from other version values, supporting the guardrails tracked in SPM-4849.