fix(blog): remove test-post.md, fix blog index slug links

- Delete extra test-post.md (scope creep from F4)
- Fix EN blog index: strip 'en/' prefix from post.id in links
- Fix RU blog index: strip 'ru/' prefix from post.id in links
- Fix schema URLs in both blog indices to use clean slugs

src/content/blog/en/test-post.md

@@ -1,12 +0,0 @@
----
-title: "Test Post"
-description: "A test blog post for verification."
-pubDate: 2025-01-15
-modDate: 2025-01-15
-draft: false
-lang: en
-category: guide
-tags: ["test"]
----
-
-This is a test blog post.

src/pages/blog/index.astro

@@ -27,7 +27,7 @@ const blogSchema = {
     headline: post.data.title,
     description: post.data.description,
     datePublished: post.data.pubDate.toISOString(),
-    url: `https://randify.pro/blog/${post.slug}/`,
+    url: `https://randify.pro/blog/${post.id.replace(/^en\//, "").replace(/\.md$/, "")}/`,
   })),
 };
 ---
@@ -69,7 +69,7 @@ const blogSchema = {
             {posts.map((post) => (
               <li>
                 <a
-                  href={`/blog/${post.slug}/`}
+                   href={`/blog/${post.id.replace(/^en\//, "").replace(/\.md$/, "")}/`}
                   class="group block rounded-xl border border-zinc-800/60 bg-zinc-900/40 p-6 hover:border-accent/40 hover:bg-zinc-900/60 transition-colors focus:outline-none focus-visible:ring-2 focus-visible:ring-accent focus-visible:ring-offset-2 focus-visible:ring-offset-zinc-950"
                 >
                   <div class="flex flex-wrap items-center gap-2 mb-3">

src/pages/ru/blog/index.astro

@@ -27,7 +27,7 @@ const blogSchema = {
     headline: post.data.title,
     description: post.data.description,
     datePublished: post.data.pubDate.toISOString(),
-    url: `https://randify.pro/ru/blog/${post.slug}/`,
+    url: `https://randify.pro/ru/blog/${post.id.replace(/^ru\//, "").replace(/\.md$/, "")}/`,
   })),
 };
 ---
@@ -69,7 +69,7 @@ const blogSchema = {
             {posts.map((post) => (
               <li>
                 <a
-                  href={`/ru/blog/${post.slug}/`}
+                   href={`/ru/blog/${post.id.replace(/^ru\//, "").replace(/\.md$/, "")}/`}
                   class="group block rounded-xl border border-zinc-800/60 bg-zinc-900/40 p-6 hover:border-accent/40 hover:bg-zinc-900/60 transition-colors focus:outline-none focus-visible:ring-2 focus-visible:ring-accent focus-visible:ring-offset-2 focus-visible:ring-offset-zinc-950"
                 >
                   <div class="flex flex-wrap items-center gap-2 mb-3">