Add ReadCSVFileWithUtf8 and use it in Z1

vba_code_common.bas

@@ -129,3 +129,25 @@ Sub WriteCSVFile(ByVal filePath As String, ByVal content As String)
         .Close
     End With
 End Sub
+
+Function ReadCSVFileWithUtf8(ByVal filePath As String) As Variant
+    If filePath = "" Then
+        ReadCSVFileWithUtf8 = Array()
+        Exit Function
+    End If
+    
+    Dim stream As Object
+    Dim textContent As String
+    
+    Set stream = CreateObject("ADODB.Stream")
+    With stream
+        .Type = 2
+        .Charset = "utf-8"
+        .Open
+        .LoadFromFile filePath
+        textContent = .ReadText
+        .Close
+    End With
+    
+    ReadCSVFileWithUtf8 = Split(textContent, vbLf)
+End Function

vba_code_kotsu_master.bas

@@ -19,7 +19,7 @@ Sub Z1_ImportMasterDetailData()
     If filePath = "" Then Exit Sub
     
     ' Step 2: Read CSV
-    lines = ReadCSVFile(filePath)
+    lines = ReadCSVFileWithUtf8(filePath)
     
     ' Step 3: Validate column count
     If Not ValidateCSVColumnCount(lines, 7) Then Exit Sub