feat(blog): add city_id to blogs for city-specific scoping

- Introduced a new nullable city_id column in the blogs table to allow scoping of blog posts to specific cities.
- Updated Blog entity to include a ManyToOne relationship with the City entity.
- Enhanced BlogController to handle city_id in the request, allowing filtering of posts by city.
- Modified BlogRepository to support querying published posts based on city_id.
- Added tests to ensure correct behavior for city-scoped and nationwide posts, including creation and updating of posts with city associations.

src/Blog/Entity/Blog.php

@@ -3,6 +3,7 @@
 namespace App\Blog\Entity;
 
 use App\Auth\Entity\User;
+use App\Location\Entity\City;
 use Doctrine\ORM\Mapping as ORM;
 use App\Blog\Repository\BlogRepository;
 use Symfony\Component\Uid\Uuid;
@@ -10,6 +11,7 @@ use Symfony\Component\Uid\Uuid;
 #[ORM\Entity(repositoryClass: BlogRepository::class)]
 #[ORM\Table(name: 'blogs')]
 #[ORM\Index(columns: ['status', 'created_at'], name: 'idx_blogs_status')]
+#[ORM\Index(columns: ['city_id'], name: 'idx_blogs_city')]
 class Blog
 {
     public const STATUS_DRAFT     = 'draft';
@@ -46,6 +48,13 @@ class Blog
     #[ORM\JoinColumn(name: 'author_id', referencedColumnName: 'id', nullable: false, onDelete: 'RESTRICT')]
     private User $author;
 
+    // شهر پست. NULL معنای دائمی دارد: «پست سراسری» که روی دامنهٔ اصلی canonical
+    // می‌شود. سایت عمومی چند-دامنه‌ای بر پایهٔ همین تفکیک تصمیم می‌گیرد پست را روی
+    // دامنهٔ شهر نشان دهد یا روی دامنهٔ اصلی.
+    #[ORM\ManyToOne(targetEntity: City::class)]
+    #[ORM\JoinColumn(name: 'city_id', referencedColumnName: 'id', nullable: true, onDelete: 'SET NULL')]
+    private ?City $city = null;
+
     #[ORM\Column(type: 'json')]
     private array $tags = [];
 
@@ -80,6 +89,7 @@ class Blog
     public function getAuthor(): User   { return $this->author; }
     public function getTags(): array    { return $this->tags; }
     public function getStatus(): string { return $this->status; }
+    public function getCity(): ?City    { return $this->city; }
 
     public function setTitle(string $v): self    { $this->title = $v; $this->touch(); return $this; }
     public function setSlug(string $v): self     { $this->slug = $v; $this->touch(); return $this; }
@@ -89,6 +99,8 @@ class Blog
     public function setImagePath(?string $v): self { $this->imagePath = $v; $this->touch(); return $this; }
     public function setTags(array $v): self      { $this->tags = $v; $this->touch(); return $this; }
     public function setStatus(string $v): self   { $this->status = $v; $this->touch(); return $this; }
+    /** null = پست سراسری (روی همهٔ دامنه‌ها، canonical روی دامنهٔ اصلی) */
+    public function setCity(?City $v): self      { $this->city = $v; $this->touch(); return $this; }
 
     private function touch(): void { $this->updatedAt = time(); }
 
@@ -112,11 +124,25 @@ class Blog
             'tags'       => $this->tags,
             'status'     => $this->status,
             'author'     => $this->authorToArray(),
+            'city'       => $this->cityToArray(),
             'created_at' => $this->createdAt,
             'updated_at' => $this->updatedAt,
         ];
     }
 
+    /** null = پست سراسری. مصرف‌کننده روی همین null تصمیم canonical می‌گیرد. */
+    private function cityToArray(): ?array
+    {
+        if ($this->city === null) {
+            return null;
+        }
+
+        return [
+            'id'   => (string) $this->city->getId(),
+            'name' => $this->city->getName(),
+        ];
+    }
+
     private function authorToArray(): ?array
     {
         if ($this->author === null) {
@@ -144,6 +170,7 @@ class Blog
             'image_url'  => $this->imageUrl,
             'tags'       => $this->tags,
             'status'     => $this->status,
+            'city'       => $this->cityToArray(),
             'created_at' => $this->createdAt,
         ];
     }