인격은 호출별 선택이고, 설정을 쪼갤 땐 살아 있는 값을 갈라

# The clean lane stays personaless: tidying markup is janitorial and
# should read as nobody. The derive lane speaks as a named character,
# because a summary is prose someone reads as somebody's words.
async def clean_article(text: str) -> str:
    result = await utility_complete(prompt, CLEAN_INSTRUCTION,
                                    lane="clean")
                                    # no persona_soul_id -> nobody
    return str(result.get("result") or "").strip()


async def summarize(text: str, lang: str) -> str:
    result = await utility_complete(
        prompt, SUMMARY_INSTRUCTION,
        lane="derive",                     # its OWN brain/effort pick
        persona_soul_id="pippa",           # opt-in, per call
        source=f"tidings-derive-summary-{lang}",
    )
    # The persona emits a trailing avatar marker that a stateless
    # completion has no use for. It is stripped INSIDE the door, by
    # the owner that defines the persona -- not here. This side just
    # takes the text. Same rule as sending the id instead of the
    # prompt: whoever owns the convention owns cleaning up after it.
    return str(result.get("result") or "").strip()


# Splitting a shared setting: fork the LIVE value, never the factory
# default. Here the two lanes chain through env defaults --
# TIDINGS_DERIVE_* falls back to TIDINGS_READER_* -- so an install
# tuned away from its defaults keeps that tuning on BOTH sides of the
# split. Seeding the new lane from config would have silently
# downgraded it: a regression arriving inside a feature.