New engine decoder, phone bench

The from-scratch decoder compiled to wasm. Nothing from the fork is on this page. It listens, decodes a window every 6 s, and shows the contour and how long the decode took. Since the evening build it also names what it hears, with our own matcher over the shipped corpus; nothing from the fork is on this page.

decodes	0
match ms, last	–
decode ms, last	–
decode ms, median	–
decode ms, p90	–
decode ms, max	–
duty cycle at 6 s cadence (median)	–
resample ms, last	–
wasm memory MB	–