feat(gateway): 全局串行化(并发=1) + 记录入参/出参/耗时日志

并发模型从「每worker并发1 + 多worker并行」改为全局串行：同一时间
只处理1个请求，其余排队；多 worker 仅作热备（主 worker 坏了才用备机）。
接口4(face/features) 走豆包、不占 GPU，不纳入串行。

- pool: asyncio.Semaphore(max_global_concurrency=1) + acquire/release_global_slot
  （依赖单进程 uvicorn 部署，已在注释中标注）
- forward: proxy_request 最外层 acquire 全局槽、try/finally 全路径释放；
  入参 multipart 解析挂 request.state；原重试/故障转移逻辑抽到 _dispatch_with_retries
- reqlog(新): 标量入参保留；图片(file/base64)存盘转URL，绝不内嵌base64；
  出参递归摘要截断(landmarks/长串/大数组)
- logging_middleware: RequestLogEntry 加 request_params/response_data，
  jsonl 全量记录；_load_from_logfile 同步映射防重启丢字段；get_stats recent 暴露
- /gateway-health 暴露 global_max/global_busy/global_waiting
- config: dispatch 新增 max_global_concurrency / max_queue_wait_seconds
- tests: test_reqlog + test_gateway_serialization（9 用例）

顺带提交此前未提交的网关统计(daily stats 接口)与耗时看板(api_timing_dashboard.html)。

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

gateway/app.py

@@ -20,6 +20,8 @@ from fastapi.staticfiles import StaticFiles
 
 from gateway.config import load_config
 from gateway.logging_middleware import (
+    get_available_dates,
+    get_daily_stats,
     get_stats,
     init_logging as _init_req_logging,
     request_logging_middleware,
@@ -185,6 +187,9 @@ async def gateway_health():
         "workers_total": status["total"],
         "workers_healthy": status["healthy"],
         "workers_busy": status["busy"],
+        "global_max": status.get("global_max", 1),
+        "global_busy": status.get("global_busy", 0),
+        "global_waiting": status.get("global_waiting", 0),
     }
 
 
@@ -201,6 +206,7 @@ async def index():
         "version": "0.1.0",
         "docs": "/docs",
         "stats": "/admin/stats",
+        "timing_dashboard": "/static/api_timing_dashboard.html",
         "integration_guide": "/static/integration.html",
         "test_pages": {
             "if1_measure": "/static/test_interface1.html",
@@ -470,6 +476,18 @@ async def admin_stats_json():
     return get_stats()
 
 
+@app.get("/admin/stats/dates", include_in_schema=False)
+async def admin_stats_dates():
+    """返回日志中出现过的所有本地日期（供耗时看板日期选择器使用）。"""
+    return {"dates": get_available_dates()}
+
+
+@app.get("/admin/stats/daily", include_in_schema=False)
+async def admin_stats_daily(date: str):
+    """按天统计各接口调用耗时（含多发型接口的单次换发型耗时拆解）。"""
+    return get_daily_stats(date)
+
+
 # ---------------------------------------------------------------------------
 # 代理路由
 # ---------------------------------------------------------------------------
@@ -529,6 +547,7 @@ async def hair_grow_b(request: Request):
 
 @app.post("/api/v1/face/features", tags=["人脸分析"])
 async def face_features(
+    request: Request,
     image_file: Optional[UploadFile] = File(default=None, description="上传图片文件（JPG/PNG）"),
     image_url: Optional[str] = Form(default=None, description="图片 URL"),
     image_base64: Optional[str] = Form(default=None, description="图片 base64（需带前缀）"),
@@ -559,6 +578,26 @@ async def face_features(
                 "request_id": f"gw-{_uuid.uuid4().hex[:8]}", "data": None,
             })
 
+    # 入参日志（接口4 不走 forward.py，自行记录；不获取全局串行槽，因不占 GPU）
+    try:
+        from gateway.config import get_config as _get_cfg
+        from gateway.reqlog import save_image_bytes
+        _cfg = _get_cfg()
+        _params: dict = {}
+        if image_file:
+            _url = save_image_bytes(img_bytes, _cfg["static_dir"], _cfg["public_base_url"]) if img_bytes else None
+            _params["image_file"] = {"_image": True, "source": "file",
+                                     "size": len(img_bytes) if img_bytes else 0, "url": _url}
+        elif image_base64:
+            _url = save_image_bytes(img_bytes, _cfg["static_dir"], _cfg["public_base_url"]) if img_bytes else None
+            _params["image_base64"] = {"_image": True, "source": "base64",
+                                       "size": len(img_bytes) if img_bytes else 0, "url": _url}
+        elif image_url:
+            _params["image_url"] = image_url
+        request.state.log_request_params = _params
+    except Exception:  # noqa: BLE001
+        request.state.log_request_params = {"_parse_error": "iface4"}
+
     from fastapi.concurrency import run_in_threadpool
     from face_features import analyze_features