docs: add BOM extraction requirements and minor code fixes

- Add BOM auto-extraction system requirements specification
- Minor property name fixes in M05_PreProcessor (.Pattern -> .pattern)
- Fix .Row property references to .row for consistency

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

VBA_BOMConverter/Modules/M05_PreProcessor.bas

@@ -71,7 +71,7 @@ End Function
 ' ------------------------------------------------------------------------------
 Private Sub LoadLcfwMapping(wsMapping As Worksheet)
     Dim lastRow As Long
-    lastRow = wsMapping.Cells(wsMapping.Rows.count, 1).End(xlUp).Row
+    lastRow = wsMapping.Cells(wsMapping.Rows.count, 1).End(xlUp).row
 
     Dim i As Long
     Dim key As String, val As String
@@ -94,7 +94,7 @@ End Sub
 ' ------------------------------------------------------------------------------
 Private Sub LoadAzxsMapping(wsMapping As Worksheet)
     Dim lastRow As Long
-    lastRow = wsMapping.Cells(wsMapping.Rows.count, 4).End(xlUp).Row
+    lastRow = wsMapping.Cells(wsMapping.Rows.count, 4).End(xlUp).row
 
     Dim i As Long
     Dim key As String, val As String
@@ -265,7 +265,7 @@ Private Function ApplyRegexMapping( _
     With regex
         .Global = True      ' 全局匹配
         .IgnoreCase = True  ' 不区分大小写
-        .Pattern = pattern
+        .pattern = pattern
     End With
 
     ' 执行匹配
@@ -309,7 +309,7 @@ Private Function ApplyRegexMapping( _
             With exactRegex
                 .Global = False  ' 只替换第一个匹配（从后向前，每次只处理一个）
                 .IgnoreCase = True
-                .Pattern = exactPattern
+                .pattern = exactPattern
             End With
 
             result = exactRegex.Replace(result, replacementStr)
@@ -629,4 +629,4 @@ Public Function GetAzxsMappedValue(key As String) As String
     Else
         GetAzxsMappedValue = ""
     End If
-End Function
+End Function