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>

.gitignore

@@ -0,0 +1,32 @@
+# Dependency directories
+node_modules/
+npm-debug.log
+yarn-debug.log
+yarn-error.log
+
+# Optional npm cache directory
+.npm
+
+# Environment variables
+.env
+
+# OS generated files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# Log files
+logs
+*.log
+
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+
+# Output directory
+output/