iddqd 0.4.2

Fixed

• The retain callbacks no longer permit the RefMut to be stashed outside them. This is technically a breaking change, but is being treated as a soundness bugfix.
• A number of soundness and resilience fixes for pathological implementations. These were found through a combination of human-driven analysis, example-based tests with Miri, chaos testing using fault injection with proptest, and adversarial code review from Claude Opus 4.7 and GPT-5.5. In particular, iddqd now more consistently preserves internal map state across panics in user code by using patterns like prepare-then-commit, index-based cleanup, cached hashes, and careful ordering of user-code execution relative to internal mutations.

Changed

• MSRV updated to Rust 1.85.