feat: 重构首页模板，双栏现代化布局 + 移动端适配

- 全新 Hero Banner：渐变背景，用户欢迎语
- 左侧最新文章卡片列表，含标题/摘要/作者/日期
- 右侧侧边栏：用户卡片（修复头像显示）、社区统计、快捷入口
- 完全重写 home.css，现代化样式，sticky 侧边栏
- 移动端适配：768px 单列布局，比例缩放
- 后端路由注入 PostService，获取最新 6 篇 approved 文章

internal/router/deps_core.go

@@ -23,6 +23,7 @@ type dependencies struct {
 	settingsCtrl    *controller.SettingsController
 	messageCtrl     *controller.MessageController
 	postCtrl        *controller.PostController
+	postService     *service.PostService
 	spaceCtrl       *controller.SpaceController
 	studioCtrl      *controller.StudioController
 	adminPostCtrl   *adminCtrl.AdminPostController

internal/router/deps_extra.go

@@ -49,7 +49,7 @@ func buildDeps(db *gorm.DB, cfg *config.Config, siteSettings *config.SiteSetting
 	return &dependencies{
 		authCtrl: authCtrl, authMdw: authMdw, maintenanceMdw: maintenanceMdw,
 		settingsCtrl: settingsCtrl,
-		messageCtrl: messageController, postCtrl: postCtrl, spaceCtrl: spaceCtrl,
+		messageCtrl: messageController, postCtrl: postCtrl, postService: postService, spaceCtrl: spaceCtrl,
 		studioCtrl: studioCtrl,
 		adminPostCtrl: adminPostCtrl,
 		adminCtrl: adminController, auditCtrl: auditController,

internal/router/frontend.go

@@ -22,9 +22,16 @@ func setupFrontendRoutes(r *gin.Engine, cfg *config.Config, d *dependencies) {
 	})
 	{
 		pages.GET("/", func(c *gin.Context) {
+			posts, total, err := d.postService.List("", 1, 6)
+			if err != nil {
+				posts = nil
+				total = 0
+			}
 			c.HTML(http.StatusOK, "home/index.html", common.BuildPageData(c, gin.H{
-				"Title":    "首页",
-				"ExtraCSS": "/static/css/home.css",
+				"Title":     "首页",
+				"ExtraCSS":  "/static/css/home.css",
+				"Posts":     posts,
+				"PostCount": total,
 			}))
 		})