feat: add script to generate default blog cover image

- Introduced a new script `make-blog-cover.mjs` to create a default cover image for blog posts.
- The image is generated in PNG format with dimensions 1200x630, suitable for Open Graph.
- Utilizes the site's branding colors and logo from `public/nobat724.svg`.
- Includes custom font styling using the Vazirmatn font.
- The generated image is saved to `public/assets/images/blog-default-cover.png`.

components/blog/detail/Caption.js

@@ -1,26 +1,32 @@
 import React from "react";
 import Image from "next/image";
 import { sanitizeHtml } from "@/lib/sanitize";
-import { imageUrl } from "@/helper";
+import { blogCover } from "@/helper";
 
 function Caption({ data }) {
-  const cover = data?.images?.[0]?.url ? imageUrl(data.images[0].url) : "";
+  // هیچ مقاله‌ای بدون تصویر نمایش داده نمی‌شود؛ نبودِ تصویر شاخص یعنی کاور برند.
+  const cover = blogCover(data);
 
   return (
     <>
-      {cover && cover.trim() !== "" && (
-        <div className="relative w-full aspect-video rounded-[8px] overflow-hidden">
-          <Image
-            src={cover}
-            alt={data?.title || "blog cover"}
-            fill
-            className="object-cover"
-          />
-        </div>
+      <div className="relative w-full aspect-video rounded-[8px] overflow-hidden">
+        <Image
+          src={cover}
+          alt={data?.title || "blog cover"}
+          fill
+          priority
+          sizes="(max-width: 1024px) 100vw, 68vw"
+          className="object-cover"
+        />
+      </div>
+      {data?.summary && (
+        <p className="mt-[16px] sm:mt-[20px] pr-[12px] border-r-[3px] border-[#E5E5E5] text-[#3B3B3B] text-[14px] md:text-[15px] lg:text-[16px] font-medium leading-[28px] md:leading-[30px]">
+          {data.summary}
+        </p>
       )}
       {data?.body?.value && (
         <div
-          className="my-[12px] sm:my-[16px] md:my-[20px] lg:my-[24px] text-[#525252] text-[14px] md:text-[15px] lg:text-[16px] font-normal leading-[26px] sm:leading-[28px] md:leading-[30px] lg:leading-[32px]"
+          className="blog-content my-[12px] sm:my-[16px] md:my-[20px] lg:my-[24px] text-[#525252] text-[14px] md:text-[15px] lg:text-[16px] font-normal leading-[26px] sm:leading-[28px] md:leading-[30px] lg:leading-[32px]"
           dangerouslySetInnerHTML={{ __html: sanitizeHtml(data.body.value) }}
         />
       )}