FE-1106: Add CheckboxGroup + RadioGroup to DS

[alex-e-leon]

🌟 What is the purpose of this PR?

Added CheckboxGroup and RadioGroup to the design system.

I also upgraded ark-ui, as the previous version did not support some fields on radio group that we use like "required". Upgrading also fixes some existing minor issues I noticed (like menu's closing during some hover operations), and will be required anyway for some upcoming components like DateInput.

I've read through the ark-ui changelog, and tested the DS, petrinaut + the hash frontend to make sure that no breaking changes apply to our ark-ui usage.

Including @CiaranMn + @kube in this PR in case you have any concerns with the ark-ui upgrade.

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

This PR:

• does not modify any publishable blocks or libraries, or modifications do not need publishing

📜 Does this require a change to the docs?

The changes in this PR:

• are internal and do not require a docs change

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Project	Deployment	Actions	Updated (UTC)
hash	Ready	Preview, Comment	Jul 1, 2026 11:31am
hashdotdesign-tokens	Ready	Preview, Comment	Jul 1, 2026 11:31am
petrinaut	Ready	Preview, Comment	Jul 1, 2026 11:31am

[cursor]

PR Summary

Medium Risk
RadioGroup is a breaking public API change for @hashintel/ds-components consumers, and the ark-ui minor-version jump affects all Ark-based primitives repo-wide; Checkbox/Radio no longer auto-link to FormField labels via context unless callers pass htmlForId.

Overview
Adds CheckboxGroup to @hashintel/ds-components and replaces RadioGroup with a new implementation aligned with Checkbox/Radio, plus bumps @ark-ui/react from 5.26.2 to 5.37.2 in the DS, hash-frontend, and petrinaut.

CheckboxGroup is a controlled multi-select built on Ark’s checkbox group: items + value/onChange, shared layout (block, inline, blockWithBorder) and size, optional maxSelectable (unchecked options disable at the cap), and group required / invalid (including a native “pick at least one” pattern). Checkbox gains htmlValue for grouped form posts; it no longer falls back to useFieldId—only explicit htmlForId wires the hidden input id.

RadioGroup drops the legacy options / onValueChange / defaultValue / variant (incl. card) API in favor of items, value/onChange, the same layouts/sizes via radio-checkbox-group-shared, and Ark RadioGroup.Root with custom Radio children (synced ids for labels/keyboard). Exported RadioGroupOption / RadioGroupProps types are removed from main.ts.

Smaller DS tweaks: left labelPlacement uses justifyContent: space-between; radio unchecked hover and checked-hover styles are adjusted. Ladle stories for both groups document layouts, sizes, and disabled states.

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[kube]

I checked Petrinaut and did not find any issue. 👍

[kube]

I removed from Merge Queue, given it was my approval that triggered it, and I suppose the real review you want is from @lunelson.