# XWUIChartCohortRetentionHeatmap

A cohort-retention heatmap backed by `XWUIChart` (`type: 'cohortRetentionHeatmap'`) that renders a grid of color-graded cells showing what fraction of each cohort remains active over successive periods. Provide one named `series` per cohort row, each holding a row of `{ x, y }` cells, and pick a `block` (1-4) and `size` preset (`sm`, `md`, `lg`).

## Basic Usage

Five cohort rows ("Row 1"-"Row 5"), each a row of seven `{ x, y }` cells ("C1"-"C7") with randomized 0-100 retention values, at the md preset.

```example
file: examples/BasicUsage.ts
html: examples/BasicUsage.html
title: Basic Usage
description: A 5-row by 7-column retention matrix rendered as a cohort heatmap at the md size preset.
```

## Weekly Signup Retention

Eight weekly signup cohorts tracked across W0-W7 with a realistic decay curve, value labels, and hover tooltips.

```example
file: examples/WeeklySignupRetention.ts
html: examples/WeeklySignupRetention.html
title: Weekly Signup Retention
description: Eight weekly signup cohorts decaying across W0-W7, with data labels and interactive tooltips.
```

## SaaS Trial Churn Cliff

Five monthly free-trial cohorts measured at days D0-D14, exposing the steep first-day activation drop-off as a churn cliff.

```example
file: examples/SaasTrialChurn.ts
html: examples/SaasTrialChurn.html
title: SaaS Trial Churn Cliff
description: Five trial cohorts over a 14-day window showing the day-1 activation cliff, block 2 with data labels.
```

```api
```