Overlapping charts improvements

[ksd4l]

Summary

A collection of UX and configuration improvements to the overlapping charts feature, covering warnings, axis behaviour, iconography, legend/axis visibility in downloads, and documentation.

Proposed Changes

Warnings

• Add a warning when switching between stacked bar chart and other chart types
• Add a warning when a saved chart type is disabled in config
• Add an admin-facing warning when a chart type currently in use is disabled

Axis Behaviour

• Always preserve $x_1$ when switching chart types
• Move continuous variables to $x_1$ automatically, if applicable

Iconography & Tooltips

• Update the overlapping attribute selection icon with a new icon
• Change the chart icon tooltip in the toolbar to simply read "chart"
• Update the chart icon in the toolbar to reflect the currently active chart type

Downloads

• Include legend and axis names in chart downloads

Documentation

• Add documentation covering new chart types and how their calculations are made

Acceptance Criteria

• A warning is displayed when the user switches from a stacked bar chart to any other chart type, using the approved copy

• $x_1$ is always preserved when switching between chart types
• If a continuous variable is present, it is automatically moved to $x_1$ where applicable

• The overlapping attribute selection icon is updated to the new icon

• The chart icon tooltip in the toolbar reads "chart"
• The chart icon in the toolbar reflects the currently active chart type
• Documentation is published covering all new chart types and their calculation methods

Design reference : Figma design link

Out of Scope

• Changes to the underlying chart calculation logic beyond what is needed to support the above
• New chart types not already included in the overlapping charts feature
• Warnings or messaging outside of the chart switching and config flows
• Modifications to download formats other than including legend and axis names