Fix blog post image upload storage

tests/Unit/BlogPostBannerUrlTest.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Tests\Unit;
+
+use App\Models\BlogPost;
+use Illuminate\Support\Facades\Storage;
+use Tests\TestCase;
+
+class BlogPostBannerUrlTest extends TestCase
+{
+    public function test_banner_url_uses_public_storage_url_for_blog_paths(): void
+    {
+        config(['app.url' => 'https://example.test']);
+
+        $post = new BlogPost;
+        $post->banner = 'blog/test.jpg';
+
+        $this->assertSame(
+            Storage::disk('public')->url('blog/test.jpg'),
+            $post->banner_url
+        );
+    }
+
+    public function test_banner_url_strips_storage_prefix(): void
+    {
+        config(['app.url' => 'https://example.test']);
+
+        $post = new BlogPost;
+        $post->banner = 'storage/blog/test.jpg';
+
+        $this->assertSame(
+            Storage::disk('public')->url('blog/test.jpg'),
+            $post->banner_url
+        );
+    }
+}