feat: 優化操作紀錄顯示與邏輯 (恢復描述欄位、支援來源標記、改進快照)

app/Models/Product.php

@@ -76,6 +76,34 @@ class Product extends Model
             ->dontSubmitEmptyLogs();
     }
 
+    public function tapActivity(\Spatie\Activitylog\Contracts\Activity $activity, string $eventName)
+    {
+        $properties = $activity->properties;
+        $attributes = $properties['attributes'] ?? [];
+        
+        // Handle Category Name Snapshot
+        if (isset($attributes['category_id'])) {
+            $category = Category::find($attributes['category_id']);
+            $attributes['category_name'] = $category ? $category->name : null;
+        }
+        
+        // Handle Unit Name Snapshots
+        $unitFields = ['base_unit_id', 'large_unit_id', 'purchase_unit_id'];
+        foreach ($unitFields as $field) {
+            if (isset($attributes[$field])) {
+                $unit = Unit::find($attributes[$field]);
+                $nameKey = str_replace('_id', '_name', $field);
+                $attributes[$nameKey] = $unit ? $unit->name : null;
+            }
+        }
+        
+        // Always snapshot self name for context (so logs always show "Cola")
+        $attributes['name'] = $this->name;
+
+        $properties['attributes'] = $attributes;
+        $activity->properties = $properties;
+    }
+
     public function warehouses(): \Illuminate\Database\Eloquent\Relations\BelongsToMany
     {
         return $this->belongsToMany(Warehouse::class, 'inventories')