Language route: English + Mandarin

Goal Add a local English + Mandarin route without regressing English. This is a contribution track, not a promised shipped feature yet. Why this matters Many users code-switch between English and Mandarin, especially in Singapore/China/Taiwan work contexts. RambleFix should only ship this when the route keeps English fast and preserves Mandarin meaning better than the default English path. Useful contributions - 10-30 representative English + Mandarin work dictation clips, with gold transcripts. - Candidate local models/runtimes that work on Apple Silicon. - Same-WAV benchmark results against the current RambleFix English path. - A small PR adding corpus/eval notes before any production routing change. Acceptance bar - Pure English quality does not regress. - Mixed English + Mandarin meaning improves on the same audio. - Runtime remains local-only. - Evidence is reproducible from checked-in scripts or clear docs. Start here Fork the repo, add findings under docs or eval notes, and link your Builderr/GitHub profile in the PR if you want attribution.