M0：灵台 Kernel 骨架（事件溯源/命台席位/瀑布总线/插件注册）与神识客户端边界，新增 POST /runs 占位闭环与测试，Alembic 基线合并为单一起点

backend/app/kernel/__init__.py

@@ -0,0 +1,78 @@
+"""极小硬核 Kernel：不变量裁决、命台并发控制、事件日志写入、Run 循环骨架。
+
+不可插拔（lingtai-runtime.md §1）；插件与 Profile 见 ``app.runtime``。
+"""
+
+from __future__ import annotations
+
+import asyncio
+
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
+
+from app.kernel.eventlog import KernelEventLog
+from app.kernel.loop import KernelRunLoop
+from app.kernel.seat import SeatManager
+from app.models.runtime import Run
+from app.runtime.bus import WaterfallBus
+from app.runtime.profile import resolve_profile
+from app.shenshi_client.client import ShenshiClient
+
+__all__ = ["Kernel", "KernelEventLog", "KernelRunLoop", "SeatManager"]
+
+
+class Kernel:
+    """门面：持有 Kernel 全部部件，供 lifespan 装配与 API 层调用。"""
+
+    def __init__(
+        self,
+        *,
+        shenshi: ShenshiClient,
+        session_factory: async_sessionmaker[AsyncSession],
+        event_log: KernelEventLog,
+        bus: WaterfallBus | None = None,
+        seats: SeatManager | None = None,
+        timeout_seconds: float = 120.0,
+    ) -> None:
+        self._sessions = session_factory
+        self.bus = bus or WaterfallBus()
+        self.seats = seats or SeatManager()
+        self.loop = KernelRunLoop(
+            event_log=event_log,
+            seats=self.seats,
+            bus=self.bus,
+            shenshi=shenshi,
+            session_factory=session_factory,
+            timeout_seconds=timeout_seconds,
+        )
+        self._tasks: set[asyncio.Task[None]] = set()
+
+    async def start_foreground_run(
+        self, *, character_id: str, prompt: str, trace_id: str | None = None
+    ) -> Run:
+        """创建 Run 行（queued）并异步启动循环；前台席位在循环内排队获取。"""
+        profile = resolve_profile()
+        async with self._sessions() as session:
+            run = Run(
+                character_id=character_id,
+                session_id=None,
+                status="queued",
+                goal=prompt[:300] if prompt else None,
+                origin="kernel",
+                model_hint=str(profile.params.get("slot", "chat")),
+            )
+            session.add(run)
+            await session.commit()
+            run_id = run.id
+
+        task = asyncio.create_task(
+            self.loop.execute(
+                run_id=run_id, character_id=character_id, prompt=prompt, trace_id=trace_id
+            )
+        )
+        self._tasks.add(task)
+        task.add_done_callback(self._tasks.discard)
+
+        async with self._sessions() as session:
+            created = await session.get(Run, run_id)
+            assert created is not None
+            return created