feat: Admin 媒体库列表、删除与同步索引

SSR /admin/media 复用 ListMedia/DeleteMedia，并支持按 ID 批量删与扫盘回填。

Co-authored-by: Cursor <cursoragent@cursor.com>

routers/web/home.go

@@ -108,6 +108,10 @@ func Register(r *gin.Engine, deps Deps, authMW *auth.AuthMiddleware) {
 		admin.GET("/badges/:id/edit", deps.AdminBadgeEditGet)
 		admin.POST("/badges/:id", deps.AdminBadgeUpdate)
 		admin.POST("/badges/:id/delete", deps.AdminBadgeDelete)
+		admin.GET("/media", deps.AdminMediaGet)
+		admin.POST("/media/delete", deps.AdminMediaBatchDeletePost)
+		admin.POST("/media/sync", deps.AdminMediaSyncPost)
+		admin.POST("/media/:id/delete", deps.AdminMediaDeletePost)
 		admin.GET("/trash", deps.AdminTrashGet)
 		admin.POST("/trash/:id/restore", deps.AdminTrashRestorePost)
 		admin.POST("/trash/:id/purge", deps.AdminTrashPurgePost)