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/xlsxwriter/chart_line.py

@@ -0,0 +1,146 @@
+###############################################################################
+#
+# ChartLine - A class for writing the Excel XLSX Line charts.
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2013-2025, John McNamara, jmcnamara@cpan.org
+#
+
+from typing import Any, Dict, Optional
+
+from . import chart
+
+
+class ChartLine(chart.Chart):
+    """
+    A class for writing the Excel XLSX Line charts.
+
+
+    """
+
+    ###########################################################################
+    #
+    # Public API.
+    #
+    ###########################################################################
+
+    def __init__(self, options: Optional[Dict[str, Any]] = None) -> None:
+        """
+        Constructor.
+
+        """
+        super().__init__()
+
+        if options is None:
+            options = {}
+
+        self.subtype = options.get("subtype")
+
+        if not self.subtype:
+            self.subtype = "standard"
+
+        self.default_marker = {"type": "none"}
+        self.smooth_allowed = True
+
+        # Override and reset the default axis values.
+        if self.subtype == "percent_stacked":
+            self.y_axis["defaults"]["num_format"] = "0%"
+
+        # Set the available data label positions for this chart type.
+        self.label_position_default = "right"
+        self.label_positions = {
+            "center": "ctr",
+            "right": "r",
+            "left": "l",
+            "above": "t",
+            "below": "b",
+            # For backward compatibility.
+            "top": "t",
+            "bottom": "b",
+        }
+
+        self.set_y_axis({})
+
+    ###########################################################################
+    #
+    # Private API.
+    #
+    ###########################################################################
+
+    def _write_chart_type(self, args) -> None:
+        # Override the virtual superclass method with a chart specific method.
+        # Write the c:lineChart element.
+        self._write_line_chart(args)
+
+    ###########################################################################
+    #
+    # XML methods.
+    #
+    ###########################################################################
+
+    def _write_line_chart(self, args) -> None:
+        # Write the <c:lineChart> element.
+
+        if args["primary_axes"]:
+            series = self._get_primary_axes_series()
+        else:
+            series = self._get_secondary_axes_series()
+
+        if not series:
+            return
+
+        subtype = self.subtype
+
+        if subtype == "percent_stacked":
+            subtype = "percentStacked"
+
+        self._xml_start_tag("c:lineChart")
+
+        # Write the c:grouping element.
+        self._write_grouping(subtype)
+
+        # Write the series elements.
+        for data in series:
+            self._write_ser(data)
+
+        # Write the c:dropLines element.
+        self._write_drop_lines()
+
+        # Write the c:hiLowLines element.
+        self._write_hi_low_lines()
+
+        # Write the c:upDownBars element.
+        self._write_up_down_bars()
+
+        # Write the c:marker element.
+        self._write_marker_value()
+
+        # Write the c:axId elements
+        self._write_axis_ids(args)
+
+        self._xml_end_tag("c:lineChart")
+
+    def _write_d_pt_point(self, index, point) -> None:
+        # Write an individual <c:dPt> element. Override the parent method to
+        # add markers.
+
+        self._xml_start_tag("c:dPt")
+
+        # Write the c:idx element.
+        self._write_idx(index)
+
+        self._xml_start_tag("c:marker")
+
+        # Write the c:spPr element.
+        self._write_sp_pr(point)
+
+        self._xml_end_tag("c:marker")
+
+        self._xml_end_tag("c:dPt")
+
+    def _write_marker_value(self) -> None:
+        # Write the <c:marker> element without a sub-element.
+        attributes = [("val", 1)]
+
+        self._xml_empty_tag("c:marker", attributes)