Harden the reply-language lock so qwen2.5:3b reliably stays in the locked
language instead of leaking the query language back in:
- reply_language_directive(): single resolver with clear precedence —
explicit OUTPUT_LANGUAGE lock wins over the Piper/Chatterbox English-only
fallback (this deployment's actual TTS is Korean MeloTTS, so the legacy
English lock was both wrong and contradicting the Korean lock).
- Stronger, override-explicit directive wording, inserted near the FRONT of
the system prompt so a small model gives it primacy over the persona.
- build_system_prompt(output_language=...): rewrite the persona's "in the
user's language" clause to the locked language so the persona stops
fighting the lock.
- docs/llm_contexts.md: document the resolver, precedence, and placement.
Live-verified on the running brain (qwen2.5:3b): Korean voice-style input
and a cold English query both return fully Korean replies with no CJK/Hanja
leak. Tests cover unset/set/agnostic/whitespace + precedence + persona rewrite.
8a2a109d5e