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/api/v1/endpoints/kernel_runs.py

@@ -0,0 +1,55 @@
+"""Kernel Run API（rewrite/1.0 新契约首个端点）。
+
+POST /api/v1/runs：创建占位前台 Run（M0 骨架），事件流经既有
+GET /api/v1/runs/{run_id}/stream 订阅（SSE + Last-Event-ID 断线续传）。
+与旧 runs 路由共存：本模块只新增 POST，不改动旧读端点（M2 重建时收敛）。
+"""
+
+from __future__ import annotations
+
+from fastapi import APIRouter, Depends, Request
+from pydantic import BaseModel, Field
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.api.v1.deps import get_current_user
+from app.db.session import get_session
+from app.kernel import Kernel
+from app.schemas.auth import CurrentUser
+from app.schemas.runtime import RunResponse
+from app.services.characters import resolve_active_character
+from app.services.runtime import get_run_response
+
+router = APIRouter(prefix="/runs", tags=["kernel"])
+
+
+class KernelRunCreate(BaseModel):
+    """占位 Run 创建请求：M0 无镜树挂载，prompt 直接作为用户输入。"""
+
+    prompt: str = Field(default="你好，请介绍一下你自己。", min_length=1, max_length=8000)
+    character_id: str | None = Field(default=None, description="缺省用当前激活人物")
+
+
+def _get_kernel(request: Request) -> Kernel:
+    kernel: Kernel | None = getattr(request.app.state, "kernel", None)
+    if kernel is None:
+        from app.core.errors import AppError
+
+        raise AppError("service_unavailable", "Kernel 运行时未就绪。", status_code=503)
+    return kernel
+
+
+@router.post("", response_model=RunResponse, status_code=200)
+async def create_kernel_run(
+    payload: KernelRunCreate,
+    request: Request,
+    user: CurrentUser = Depends(get_current_user),
+    db: AsyncSession = Depends(get_session),
+) -> RunResponse:
+    kernel = _get_kernel(request)
+    character = await resolve_active_character(
+        db, payload.character_id, owner_scope=user.owner_scope
+    )
+    run = await kernel.start_foreground_run(
+        character_id=character.id, prompt=payload.prompt
+    )
+    return await get_run_response(run.id)