feat: 视频缩略图生成、最近文件面板与前端视图重构

- 新增 VideoThumbnailService，基于 ffmpeg 截取视频缩略图，ffprobe 提取时长
  - 新增 ManagedThumbnailMap 模型及多数据库迁移，存储缩略图元数据
  - 新增 /api/thumbnails/{id} 缩略图流端点
  - 新增最近添加/最近播放 API 与前端面板，支持列表/网格双视图切换
  - FileRecordDto 扩展 thumbnailUrl、videoDuration、lastPlayedAt 字段
  - 前端新增文件库 Tab 导航、卡片网格视图、视频海报与时长信息栏
  - 添加文件库目录不再同步全量扫描，改为后台异步自动扫描

FileShare-API/Configuration/ServicesConfiguration.cs

@@ -40,6 +40,14 @@ namespace FileShare_API.Configuration
 
             // ---- 业务服务 ----
             services.AddScoped<WeatherForecastService>();
+            var thumbnailOptions = configuration
+                .GetSection(nameof(ThumbnailStorageOptions))
+                .Get<ThumbnailStorageOptions>()
+                ?? new ThumbnailStorageOptions();
+            services.AddSingleton(thumbnailOptions);
+            services.AddSingleton<IVideoThumbnailService>(sp =>
+                new VideoThumbnailService(sp.GetRequiredService<ThumbnailStorageOptions>()));
+            services.AddScoped<IThumbnailStreamService, ThumbnailStreamService>();
             services.AddScoped<IFileLibraryService, FileLibraryService>();
             services.AddScoped<IFileLibraryEndpointService, FileLibraryEndpointService>();
             services.AddScoped<IFileStreamService, FileStreamService>();

FileShare-API/Extensions/FileStreamEndpointExtensions.cs

@@ -43,6 +43,35 @@ namespace FileShare_API.Extensions
                 .WithName("StreamManagedFileById")
                 .WithTags("FileLibrary");
 
+            app.MapMethods(
+                    "/api/thumbnails/{id:int}",
+                    ["GET", "HEAD"],
+                    async (int id, IThumbnailStreamService thumbnailStreamService, HttpContext httpContext) =>
+                    {
+                        var thumbnail = await thumbnailStreamService.GetThumbnailAsync(id);
+                        if (thumbnail is null)
+                        {
+                            return Results.NotFound();
+                        }
+
+                        var stream = System.IO.File.Open(
+                            thumbnail.FilePath,
+                            FileMode.Open,
+                            FileAccess.Read,
+                            FileShare.ReadWrite);
+
+                        httpContext.Response.Headers.ContentDisposition =
+                            $"inline; filename=\"{Uri.EscapeDataString(thumbnail.FileName)}\"";
+                        httpContext.Response.Headers.CacheControl = "public, max-age=3600";
+
+                        return Results.File(
+                            stream,
+                            contentType: thumbnail.ContentType,
+                            lastModified: thumbnail.LastModified);
+                    })
+                .WithName("StreamManagedThumbnailById")
+                .WithTags("FileLibrary");
+
             return app;
         }
     }

FileShare-API/FileShare-API.csproj

@@ -26,6 +26,8 @@
 
   <ItemGroup>
     <Folder Include="Controllers\" />
+    <Content Include="..\tools\ffmpeg\bin\ffmpeg.exe" Link="tools\ffmpeg\bin\ffmpeg.exe" CopyToOutputDirectory="PreserveNewest" CopyToPublishDirectory="PreserveNewest" />
+    <Content Include="..\tools\ffmpeg\bin\ffprobe.exe" Link="tools\ffmpeg\bin\ffprobe.exe" CopyToOutputDirectory="PreserveNewest" CopyToPublishDirectory="PreserveNewest" />
   </ItemGroup>
 
   <Target Name="RestoreFrontendPackages" BeforeTargets="Build" Condition="'$(SkipFrontendBuild)' != 'true' And Exists('..\FileShare-Web-VUE\package.json') And !Exists('..\FileShare-Web-VUE\node_modules')">

FileShare-API/appsettings.json

@@ -24,5 +24,10 @@
     "RecreateDatabase": false,
     "EnableDetailedLog": false,
     "Timeout": 30
+  },
+  "ThumbnailStorageOptions": {
+    "RootPath": "thumbnails",
+    "FfmpegPath": "tools/ffmpeg/bin/ffmpeg.exe",
+    "FfprobePath": "tools/ffmpeg/bin/ffprobe.exe"
   }
 }