speech-world: record the deferral reason (faithful WORLD port or WASM build — not a watered-down namesake)

Author: dy

packages/speech-world/README.md

@@ -2,4 +2,8 @@
 
 > WORLD-style vocoder — source-filter decomposition: F0 + spectral envelope + aperiodicity (Morise 2016)
 
-Planned — not implemented yet. See the umbrella README for status and sources.
+**Deferred — deliberately.** WORLD is a flagship-scale port (DIO/Harvest F0, CheapTrick envelope,
+D4C aperiodicity, ~5k lines of reference C++). A watered-down "world-like" pipeline would carry the
+name without the quality; the honest options are a faithful port or a WASM build of the reference —
+both their own project. Interim coverage: `@audio/speech-lpc` (envelope), `@audio/pitch-pyin` (F0),
+`@audio/voice-glottis` + `@audio/voice-tract` (synthesis side).