Add xlsxwriter-based Excel generation scripts with openpyxl implementation

- Created create_excel_xlsxwriter.py and update_excel_xlsxwriter.py
- Uses openpyxl exclusively to preserve Excel formatting and formulas
- Updated server.js to use new xlsxwriter scripts for form submissions
- Maintains all original functionality while ensuring proper Excel file handling

🤖 Generated with [Claude Code](https://claude.ai/code)

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

venv/lib/python3.12/site-packages/openpyxl/drawing/relation.py

@@ -0,0 +1,17 @@
+# Copyright (c) 2010-2024 openpyxl
+
+from openpyxl.xml.constants import CHART_NS
+
+from openpyxl.descriptors.serialisable import Serialisable
+from openpyxl.descriptors.excel import Relation
+
+
+class ChartRelation(Serialisable):
+
+    tagname = "chart"
+    namespace = CHART_NS
+
+    id = Relation()
+
+    def __init__(self, id):
+        self.id = id