docs(swagger): update dp_claude_cross_upstream description to include Google-family providers

Clarify that the dp_claude_cross_upstream feature flag controls routing
of Claude protocol requests to both OpenAI-compatible and Google-family
upstream providers.

docs/api.md

@@ -117,7 +117,7 @@ graph TD
 | 配置项 | 类型 | 说明 | 默认值 |
 | :--- | :--- | :--- | :--- |
 | `dp_state_store_backend` | string | 状态存储后端：`memory` (单机) / `redis` (集群)。 | `memory` |
-| `dp_claude_cross_upstream` | bool | 是否允许将 Claude 协议请求路由到 OpenAI 兼容上游。 | `true` |
+| `dp_claude_cross_upstream` | bool | 是否允许将 Claude 协议请求路由到 OpenAI 兼容与 Google-family 上游。 | `true` |
 | `log_request_body_enabled` | bool | 是否在日志中记录请求体（注意隐私风险）。 | `true` |
 | `log_retention_days` | int | 日志保留天数。写入 Redis `meta:log:retention_days`。 | `30` |
 | `log_max_records` | int | 最大日志保留条数。写入 Redis `meta:log:max_records`。 | `1000000` |

docs/swagger.json

@@ -710,7 +710,7 @@
                         "AdminAuth": []
                     }
                 ],
-                "description": "Updates selected feature flags (meta:features). Values are stored as strings.",
+                "description": "Updates selected feature flags (meta:features). Values are stored as strings. Example: dp_claude_cross_upstream controls whether /v1/messages can route to OpenAI/compatible and Google-family providers.",
                 "consumes": [
                     "application/json"
                 ],
@@ -4999,4 +4999,4 @@
             "in": "header"
         }
     }
-}
+}

docs/swagger.yaml

@@ -1400,7 +1400,8 @@ paths:
       consumes:
       - application/json
       description: Updates selected feature flags (meta:features). Values are stored
-        as strings.
+        as strings. Example: dp_claude_cross_upstream controls whether /v1/messages
+        can route to OpenAI/compatible and Google-family providers.
       parameters:
       - description: Feature map
         in: body