fix: gate and repair the Moonshot memory example

[josedab]

Summary

• Replaces the fictional example API with the real Moonshot client and correctly feature-gates compilation.
• Preserves repository public contracts while restoring or strengthening the verification baseline.
• Includes an AUDIT.md where the repository reached the audit/refactor phase.

Commits

• 78a4c29 fix(rust-sdk): gate and repair memory example

Validation

Default 216 tests and Moonshot 12 tests pass locally.

Known blockers / deferred work

• Repository-wide rustfmt and strict Clippy remain red outside this focused repair.

Merge readiness

Draft — do not merge until the blocker above is resolved or explicitly waived by maintainers.