Make profile maps optional in H2 Next

[willmot]

H2 Next renders a broken map image when a profile has no coordinates. Require both coordinates and a Mapbox key before rendering maps in the hovercard and profile sidebar, and keep hovercards available when no Mapbox key is configured.

Backports the optional-map behavior already present in the main H2 release to next. Adds a Storybook example for a profile without coordinates.

Before and after, using a synthetic profile with a Mapbox key configured and no coordinates:

- Written by Codex gpt-6-astra high

[github-actions]

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