### Fixed
- AbstractCore effect-handler media materialization now preserves artifact `content_type`, media `type`, artifact ids, and safe filename extensions instead of dropping artifact-backed media to bare paths. This keeps generated WAV artifacts valid for downstream transcription nodes.
- Added explicit MIME extension aliases for common generated media types such as `audio/wav`, `image/png`, and `video/mp4` so platform MIME table differences do not create extensionless temp files.

### Changed
- Minimum AbstractCore optional dependency floor is now `abstractcore>=2.13.14`.
