Normalize the observed AI SILK container marker at the shared audio transcode boundary before invoking the bundled decoder. Preserve caller-owned bytes and leave ordinary SILK, AMR, and unrelated inputs unchanged.
Add unit and packaged-addon regression coverage for MP3 conversion, payload preservation, and input immutability.
Fixes#268
Replace the feature-specific MP3 verification command with a workspace-wide native test entry point.
Keep native regression cases in package-owned test suites so future checks can expand without adding workflow steps.