FCPE WASM + ONNX Browser Smoke Test

Pipeline: embedded WAV -> Rust WASM mel preprocess -> ONNX model -> local-argmax decoder -> f0 curve.

Model: web/static/fcpe.single.fp16.onnx, Audio: web/static/sample.wav

Use HQ bundle (larger, includes ensemble APIs) Use sinc resampling (higher quality, slower) MIDI out (quantized semitones)