Builds the "Voice & manner" system-prompt section from the effective voice persona —
appended to the server-built companion system prompt at mint. Returns an empty string when
neither tone nor speakingStyle is configured (the section simply doesn't appear).
Builds the "Voice & manner" system-prompt section from the effective voice persona — appended to the server-built companion system prompt at mint. Returns an empty string when neither
tonenorspeakingStyleis configured (the section simply doesn't appear).