Why

The library and demo app did not provide a histogram chart, so users could not model discrete frequency distributions with the same API/style approach as other chart types.

Summary

This PR adds a new charts-histogram module with validation, style configuration, composables, previews, and tests. It wires histogram samples into shared demo data and surfaces a full histogram demo screen in the app navigation, gallery, and previews. The Android screenshot pipeline is updated with histogram screenshot tests and references. Build configuration, BOM, and module lists are updated so histogram artifacts are published and consumable.

Changes

• Add charts-histogram module (HistogramChart, style model, validation, previews, tests, and Gradle config)
• Register histogram module in settings, BOM, root build configuration, and published module lists
• Add histogram sample use case and fixtures in charts-demo-shared
• Add histogram demo UI, view model, style controls, strings, and app navigation/gallery wiring
• Add Android screenshot tests and reference images for histogram previews
• Update docs GIF scenarios to include histogram demos

Release/Changeset

• Created: ../charts-docs/content/snapshot/changes/413-add-histogram-chart.md
• Docs PR: docs(histogram): add changeset and wiki updates for charts pr 413 charts-docs#16
• Playground PR: feat(histogram): add histogram playground support charts-playground#12

Notes/Risk

• Adds a new public chart module and app demo surface; screenshot baselines and sample data are updated accordingly.