feat: 完善统一端点响应与请求绑定框架

- 新增 IApiResponse 统一响应契约，覆盖普通响应和分页响应
- 扩展端点映射，支持 IApiResponse 和带请求 DTO 的 MapXxx 重载
- 增加 Body、Query、Route Values 到请求 DTO 的自动绑定
- 增加 PC 端路由模式匹配，支持 {id} 和 {id:int}
- API 与 PC 端点上下文补充路由参数传递
- 调整 OpenAPI 请求类型处理，避免 GET/DELETE 被标记为 JSON Body
- 鉴权端点迁移到强类型请求绑定和 IApiResponse 返回
- 增加统一端点文件流响应支持

Avalonia-API/Extensions/UnifiedEndpointExtensions.cs

@@ -81,7 +81,8 @@ namespace Avalonia_API.Extensions
                     routeHandlerBuilder.WithSummary(endpoint.OpenApiSummary);
                 }
 
-                if (endpoint.OpenApiRequestType is not null)
+                if (endpoint.OpenApiRequestType is not null
+                    && endpoint.HttpMethod is "POST" or "PUT")
                 {
                     routeHandlerBuilder.Accepts(endpoint.OpenApiRequestType, "application/json");
                 }
@@ -131,9 +132,11 @@ namespace Avalonia_API.Extensions
         {
             return async (HttpContext httpContext) =>
             {
-                var ctx = await BuildContextFromHttpContext(httpContext);
+                var ctx = httpContext.Items["UnifiedContext"] as ServiceEndpointContext
+                    ?? await BuildContextFromHttpContext(httpContext);
                 ctx.Items["ServiceProvider"] = serviceProvider;
                 ctx.Items["User"] = httpContext.User;
+                httpContext.Items["UnifiedContext"] = ctx;
 
                 var result = await unifiedHandler(ctx);
 
@@ -144,6 +147,23 @@ namespace Avalonia_API.Extensions
                     httpContext.Response.Headers[kvp.Key] = kvp.Value;
                 }
 
+                if (result is FileStreamResponse fileResponse)
+                {
+                    if (!System.IO.File.Exists(fileResponse.FilePath))
+                        return Results.NotFound();
+
+                    var stream = System.IO.File.Open(fileResponse.FilePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+                    httpContext.Response.Headers.ContentDisposition = $"inline; filename=\"{Uri.EscapeDataString(fileResponse.FileName)}\"";
+                    httpContext.Response.Headers.AcceptRanges = "bytes";
+                    httpContext.Response.Headers.CacheControl = "public, max-age=3600";
+
+                    return Results.File(
+                        stream,
+                        contentType: fileResponse.ContentType,
+                        lastModified: fileResponse.LastModified,
+                        enableRangeProcessing: true);
+                }
+
                 return result is not null ? Results.Json(result) : Results.Ok();
             };
         }
@@ -173,6 +193,14 @@ namespace Avalonia_API.Extensions
                 ctx.Query[query.Key] = query.Value.ToString();
             }
 
+            foreach (var routeValue in httpContext.Request.RouteValues)
+            {
+                if (routeValue.Value is not null)
+                {
+                    ctx.RouteValues[routeValue.Key] = routeValue.Value.ToString() ?? string.Empty;
+                }
+            }
+
             if (httpContext.Request.ContentLength > 0)
             {
                 using var reader = new StreamReader(httpContext.Request.Body);
@@ -204,6 +232,7 @@ namespace Avalonia_API.Extensions
 
             httpContext.Items["UnifiedContext"] = ctx;
 
+            object? nextResult = null;
             await unifiedFilter.InvokeAsync(ctx, async (c) =>
             {
                 httpContext.Response.StatusCode = c.StatusCode;
@@ -211,7 +240,7 @@ namespace Avalonia_API.Extensions
                 {
                     httpContext.Response.Headers[kvp.Key] = kvp.Value;
                 }
-                await aspNext(aspContext);
+                nextResult = await aspNext(aspContext);
             });
 
             if (ctx.ResponseBody is not null)
@@ -219,7 +248,7 @@ namespace Avalonia_API.Extensions
                 return Results.Json(ctx.ResponseBody, statusCode: ctx.StatusCode);
             }
 
-            return null!;
+            return nextResult;
         }
     }
 }