feat(bot): tool-using chat agent over RAG, ЕМИАС record and drug-safety reference

Free-text treatment and medication questions go to an LLM agent with read-only tools bound to the current
patient: guideline search (RAG, doses stripped), ЕМИАС record mock (diagnoses, comorbidities, intolerances,
other specialists' drugs, current prescription), drug info (composition, contraindications, interactions)
and a deterministic patient-specific check. Providers: OpenRouter (temporary, synthetic data only) and an
offline mock; GigaChat to follow. Scrubbed input only, forbidden-output filter, any failure falls back to
the existing extractive RAG / instruction answers. Off unless OPENROUTER_API_KEY or CHAT_AGENT=mock.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/llm/agent/__main__.py

@@ -0,0 +1,59 @@
+"""Try the chat agent from the shell (synthetic personas only):
+
+    uv run python -m app.llm.agent "Можно мне ибупрофен вместе с моими таблетками?" --persona andrey
+    CHAT_AGENT=mock uv run python -m app.llm.agent "Есть ли лактоза в сертралине?"
+
+Prescriptions come from the МИС mock (DB if reachable, else data/meds/mis_prescriptions.json); the question is
+scrubbed before it reaches any provider.
+"""
+
+import argparse
+import asyncio
+import logging
+
+from app.config import get_settings
+from app.core.privacy import pseudo_id, scrub
+from app.integrations.base import Prescription, integrations
+from app.llm.agent import answer_chat, build_provider, render
+
+PERSONAS = {  # synthetic SNILS from scripts/seed_demo.py → current psychiatric prescription
+    "andrey": ("900-000-013 34", "сертралин"),
+    "dmitry": ("900-000-041 01", "сертралин"),
+    "sergey": ("900-000-037 02", "пароксетин"),
+    "nikolay": ("900-000-052 03", "сертралин"),
+    "anna": ("900-000-023 04", "флуоксетин"),
+    "pavel": ("900-000-045 07", "эсциталопрам"),
+}
+
+
+class _FixedRx:
+    def __init__(self, drug: str) -> None:
+        self.drug = drug
+
+    async def get_prescriptions(self, token: str) -> list[Prescription]:
+        return [Prescription(drug=self.drug, dose="по назначению врача")]
+
+
+async def main() -> None:
+    p = argparse.ArgumentParser()
+    p.add_argument("question")
+    p.add_argument("--persona", default="andrey", choices=sorted(PERSONAS))
+    p.add_argument("-v", "--verbose", action="store_true")
+    a = p.parse_args()
+    logging.basicConfig(level=logging.INFO if a.verbose else logging.WARNING)
+    snils, drug = PERSONAS[a.persona]
+    integrations.prescriptions = _FixedRx(drug)  # CLI runs without the DB
+    provider = build_provider()
+    if provider is None:
+        raise SystemExit(
+            f"agent disabled (CHAT_AGENT={get_settings().chat_agent}); set OPENROUTER_API_KEY or CHAT_AGENT=mock"
+        )
+    ans = await answer_chat(pseudo_id(snils), scrub(a.question), provider=provider)
+    if ans is None:
+        raise SystemExit("no answer (provider error, filtered output or nothing found) — chat falls back to RAG")
+    print(render(ans))
+    print(f"\n[provider={ans.provider} tools={', '.join(ans.tools)}]")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())