Add MetricUI to data-viz category

[mpmcgowen]

Adds MetricUI to the data-viz category.

MetricUI is a React component library for building analytics dashboards — KPI cards, charts (area, line, bar, donut, heatmap, funnel, waterfall, gauge), data tables, and layout components with built-in formatting, theming, and data state handling.

• Demo: https://metricui.com/demos
• npm: metricui
• License: MIT

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Summary by cubic

Add MetricUI to the data-viz category to expand our catalog of React analytics components. Includes GitHub repo, metricui npm package, and demo URL for quick discovery.

^{Written for commit a436e8d. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 1 file

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