docs: 品牌全量口径统一为「南方基金」+ 作废文档清理

1) 客服 Agent 四份交付文档 + 构建脚手架：品牌由包装占位 XX科技 / 旧名 南方财富
   统一为南方基金（热线 400-889-8899 / 官网 nffund.com），系统名改为「智能服务系统」；
   同步追加 §0.4 修订记录行，工程记录行保留原占位字面以支撑硬编码扫描验收。
2) 开发文档：清理 28 份已作废/残留文档（14 份移出归档 + 14 份仓库副本），
   新增《文档规整方案与开发前待决事项-2026-09-17》。
3) 客服agent 四份交付文档首次纳入本分支。

tests/integration/test_worker_lease.py

@@ -0,0 +1,60 @@
+from datetime import UTC, datetime, timedelta
+from uuid import uuid4
+
+import pytest
+from sqlalchemy import delete, update
+
+from app.infrastructure.db import SessionFactory
+from app.model.conversation import ConversationMessage
+from app.model.platform import AgentRun, RequestIdempotency
+from app.repository.agent_run_repository import AgentRunRepository
+
+
+@pytest.mark.integration
+@pytest.mark.asyncio
+async def test_worker_lease_renew_and_takeover() -> None:
+    now = datetime.now(UTC).replace(tzinfo=None)
+    session_id = f"lease-{uuid4()}"
+    run_id = str(uuid4())
+    trace_id = str(uuid4())
+    async with SessionFactory() as session:
+        idem = RequestIdempotency(
+            user_id=1, session_id=session_id, agent_type="customer_service",
+            idempotency_key=f"lease-key-{uuid4()}", request_hash="a" * 64,
+            trace_id=trace_id, status="processing", expire_at=now + timedelta(hours=1),
+            created_at=now, updated_at=now,
+        )
+        message = ConversationMessage(
+            session_id=session_id, customer_id=1, portal="api", role="user",
+            content="lease test", trace_id=trace_id, created_at=now,
+        )
+        session.add_all([idem, message])
+        await session.flush()
+        run = AgentRun(
+            run_id=run_id, idempotency_id=idem.id, session_id=session_id, user_id=1,
+            agent_type="customer_service", trace_id=trace_id, request_message_id=message.id,
+            created_at=now, updated_at=now,
+        )
+        session.add(run)
+        await session.commit()
+        try:
+            repo = AgentRunRepository(session)
+            assert await repo.claim(run_id, "worker-a", 60)
+            assert await repo.renew(run_id, "worker-a", 60)
+            assert not await repo.claim(run_id, "worker-b", 60)
+            await session.execute(
+                update(AgentRun).where(AgentRun.run_id == run_id).values(
+                    locked_until=now - timedelta(seconds=1)
+                )
+            )
+            await session.commit()
+            assert await repo.claim(run_id, "worker-b", 60)
+        finally:
+            await session.execute(delete(AgentRun).where(AgentRun.run_id == run_id))
+            await session.execute(
+                delete(RequestIdempotency).where(RequestIdempotency.id == idem.id)
+            )
+            await session.execute(
+                delete(ConversationMessage).where(ConversationMessage.session_id == session_id)
+            )
+            await session.commit()