refactor: update several relationship methods from HasMany to HasOne and singularize relationship names.

app/Models/Cooperation.php

@@ -8,8 +8,8 @@
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
-use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\HasManyThrough;
+use Illuminate\Database\Eloquent\Relations\HasOne;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Spatie\MediaLibrary\HasMedia;
 use Spatie\MediaLibrary\InteractsWithMedia;
@@ -62,21 +62,21 @@ protected function completed(Builder $query): void
         $query->where('status', CooperationStatus::COMPLETED);
     }
 
-    public function cooperationMedias(): HasMany
+    public function cooperationMedia(): HasOne
     {
-        return $this->hasMany(CooperationMedia::class);
+        return $this->hasOne(CooperationMedia::class);
     }
 
-    public function partnerMedias(): BelongsToMany
+    public function partnerMedia(): BelongsToMany
     {
         return $this->belongsToMany(PartnerMedia::class, 'cooperation_media')
             ->withPivot(['status'])
             ->withTimestamps();
     }
 
-    public function proposals(): HasMany
+    public function proposal(): HasOne
     {
-        return $this->hasMany(CooperationProposal::class);
+        return $this->hasOne(CooperationProposal::class);
     }
 
     public function reports(): HasManyThrough
@@ -84,8 +84,8 @@ public function reports(): HasManyThrough
         return $this->hasManyThrough(Report::class, TaskAssignment::class);
     }
 
-    public function taskAssignments(): HasMany
+    public function taskAssignment(): HasOne
     {
-        return $this->hasMany(TaskAssignment::class);
+        return $this->hasOne(TaskAssignment::class);
     }
 }