✨ feat: 阶段 0 收尾——认证边界、请求上下文与垂直切片（WP-01 第 5-7 步）

- 认证：Web Session（__Host- Cookie、HttpOnly/Secure/SameSite=Lax、CSPRNG opaque token 数据库只存哈希）、CSRF 双提交、Origin 校验、dev 登录/登出端点；未认证 401、缺 CSRF 403
- 中间件：Hunjing-Request-ID 回显/生成（request_ UUIDv4）+ W3C traceparent 校验透传；JSON 结构化日志与敏感头脱敏
- 迁移 2：conversation/branch/message/run/idempotency_record 五表（含检查约束与复合索引）；Session 补 token/csrf 哈希列
- 垂直切片：POST /v1/conversations/{id}/messages 按 Idempotency-Key 幂等（同键同体 200 重放、异体 409），同事务原子写 Message+Run+Audit+Outbox+幂等记录；ContentBlock text/markdown 判别联合（未知类型 422）
- SSE：GET /v1/runs/{id}/events 返回快照与终止状态事件 envelope
- 测试 26 项全绿：IDOR 跨域 404 fail-closed、失败注入回滚无孤儿（Run 崩溃后 message/run/audit/outbox/幂等全零）、SSE 事件序、auth 边界；ruff/mypy strict 干净
- 修复真实问题：asyncpg 跨事件循环（anyio/pytest-asyncio 双 loop、模块级 engine 改为 app 实例持有）、httpx 拒存 http 下 Secure Cookie

backend/app/core/middleware.py

@@ -0,0 +1,80 @@
+"""请求上下文中间件与结构化日志。
+
+- `Hunjing-Request-ID`：合法则回显，缺失由服务端生成（UUIDv4，request_ 前缀）。
+- `traceparent`：透传 W3C Trace Context；缺失生成新 trace-id（不与业务请求 ID 混用）。
+- JSON 结构化日志：Authorization/Cookie/Set-Cookie 等敏感头脱敏。
+"""
+
+import json
+import logging
+import re
+import uuid
+from typing import Any
+
+from starlette.middleware.base import BaseHTTPMiddleware
+from starlette.requests import Request
+
+from app.core.ids import new_id
+
+REDACTED_HEADERS = {"authorization", "cookie", "set-cookie", "hunjing-csrf-token", "x-api-key"}
+_TRACEPARENT_RE = re.compile(r"^[0-9a-f]{2}-[0-9a-f]{32}-[0-9a-f]{16}-[0-9a-f]{2}$")
+
+
+def _sanitize_headers(headers: Any) -> dict[str, str]:
+    return {
+        k: ("[REDACTED]" if k.lower() in REDACTED_HEADERS else v) for k, v in headers.items()
+    }
+
+
+class JsonFormatter(logging.Formatter):
+    def format(self, record: logging.LogRecord) -> str:
+        payload: dict[str, Any] = {
+            "ts": self.formatTime(record, "%Y-%m-%dT%H:%M:%S%z"),
+            "level": record.levelname,
+            "logger": record.name,
+            "message": record.getMessage(),
+        }
+        for key in ("request_id", "trace_id", "method", "path", "status"):
+            value = getattr(record, key, None)
+            if value is not None:
+                payload[key] = value
+        if record.exc_info:
+            payload["exception"] = self.formatException(record.exc_info)
+        return json.dumps(payload, ensure_ascii=False)
+
+
+def configure_logging(level: str = "info") -> None:
+    handler = logging.StreamHandler()
+    handler.setFormatter(JsonFormatter())
+    root = logging.getLogger()
+    root.handlers = [handler]
+    root.setLevel(level.upper())
+
+
+class RequestContextMiddleware(BaseHTTPMiddleware):
+    async def dispatch(self, request: Request, call_next: Any) -> Any:
+        request_id = request.headers.get("Hunjing-Request-ID") or new_id("request_", version=4)
+        traceparent = request.headers.get("traceparent")
+        if traceparent is None or not _TRACEPARENT_RE.match(traceparent):
+            traceparent = f"00-{uuid.uuid4().hex}-{uuid.uuid4().hex[:16]}-01"
+        trace_id = traceparent.split("-")[1]
+        request.state.request_id = request_id
+        request.state.trace_id = trace_id
+
+        response = await call_next(request)
+        response.headers["Hunjing-Request-ID"] = request_id
+        response.headers["traceparent"] = traceparent
+        logging.getLogger("hunjing.access").info(
+            "request",
+            extra={
+                "request_id": request_id,
+                "trace_id": trace_id,
+                "method": request.method,
+                "path": request.url.path,
+                "status": response.status_code,
+            },
+        )
+        return response
+
+
+__all__ = ["RequestContextMiddleware", "configure_logging", "_sanitize_headers"]