docs(zonos-gateway): dials-first emotion spec (operator ruling)

Canonical direction: emotion set by twisting raw dials per-utterance, not preset
selection. Presets demoted to optional examples. Spec covers the dial vocabulary
+ ranges, the emotion_cfg_scale 'deaf by 1.5' rule (NO cap — documented ceiling,
explicit over implicit), measured RTF cost, starting-point dial-sets, an LLM
client system-prompt snippet, and clone reference guidance (~15-24s, no
transcript). Follow-ups flagged: align dials.py cfg help/metadata, trim in-code
PRESETS pending usage check, stand up vh/zonos-gateway for version control.

stacks/zonos-gateway/README.md

@@ -41,7 +41,17 @@ one-line alias repoint, invisible to every consumer. This repo stays
 Zonos-specific (voice registry, correct native defaults, presets); the swap
 point is the alias, not the code.
 
-## Emotion control — the simple caller path (presets)
+## Emotion control
+
+> **Direction (operator ruling 2026-07-17): dials-first.** Emotion is set by
+> twisting the raw dials per-utterance; presets are demoted to optional
+> copy-and-tweak examples, not the primary interface. See
+> [`EMOTION-DIALS-SPEC.md`](EMOTION-DIALS-SPEC.md) for the dial vocabulary, the
+> `emotion_cfg_scale` "deaf by 1.5" rule (no cap, documented ceiling), the
+> LLM-client system-prompt snippet, and reference-voice guidance. The
+> preset-centric description below is retained as background.
+
+### (background) the preset path
 
 Emotion is exposed as **named presets** that bundle the engine's steering knobs
 (`emotion_sliders` / `emotion_valence` / `emotion_arousal` / `emotion_strength`