feat: 新增採購單發票欄位、更新 SearchableSelect 樣式與搜尋門檻至 10 個項目

app/Models/PurchaseOrder.php

@@ -22,13 +22,18 @@ class PurchaseOrder extends Model
         'tax_amount',
         'grand_total',
         'remark',
+        'invoice_number',
+        'invoice_date',
+        'invoice_amount',
     ];
 
     protected $casts = [
         'expected_delivery_date' => 'date',
+        'invoice_date' => 'date',
         'total_amount' => 'decimal:2',
         'tax_amount' => 'decimal:2',
         'grand_total' => 'decimal:2',
+        'invoice_amount' => 'decimal:2',
     ];
 
     protected $appends = [
@@ -40,6 +45,9 @@ class PurchaseOrder extends Model
         'createdBy',
         'warehouse_name',
         'createdAt',
+        'invoiceNumber',
+        'invoiceDate',
+        'invoiceAmount',
     ];
 
     public function getCreatedAtAttribute()
@@ -82,6 +90,22 @@ class PurchaseOrder extends Model
         return $this->warehouse ? $this->warehouse->name : '';
     }
 
+    public function getInvoiceNumberAttribute(): ?string
+    {
+        return $this->attributes['invoice_number'] ?? null;
+    }
+
+    public function getInvoiceDateAttribute(): ?string
+    {
+        $date = $this->attributes['invoice_date'] ?? null;
+        return $date ? \Illuminate\Support\Carbon::parse($date)->format('Y-m-d') : null;
+    }
+
+    public function getInvoiceAmountAttribute(): ?float
+    {
+        return isset($this->attributes['invoice_amount']) ? (float) $this->attributes['invoice_amount'] : null;
+    }
+
     public function vendor(): BelongsTo
     {
         return $this->belongsTo(Vendor::class);