feat(radio): add RadioGroup component (CUI-17)

[JeanMarcMilletScality]

Summary

• Adds RadioGroup as the public API for radio inputs — options-driven, controlled component that owns selection, shared name, accessible label, and disabled state.
• Accessible name comes from one of label (renders <fieldset>/<legend>), aria-label, or aria-labelledby — supports FormGroup integration without duplicating the label.
• Per-option disabledReason shown as a tooltip on hover; group-level disabled cascades to every option.
• Removes the standalone Radio export (was unused outside the repo); Radio.component.tsx is gone.

Ref: CUI-17

Test plan

• npx jest --testPathPatterns=radio passes (9 behavioural tests covering label sources, selection, mutual exclusivity, disabled cascade, single-option disable, shared name, disabledReason tooltip)
• npx tsc --noEmit clean
• npm run lint clean
• Storybook (npm run storybook): visit Components/Inputs/Radio and verify RadioGroupExample, Horizontal, AllStates, DisabledGroup, WithDisabledReason, WithoutVisibleLabel, FormGroupExample
• Verify screen-reader announces the group name in each labelling mode (legend, aria-label, aria-labelledby)

🤖 Generated with Claude Code

[bert-e]

Hello jeanmarcmilletscality,

My role is to assist you with the merge of this
pull request. Please type @bert-e help to get information
on this process, or consult the user documentation.

Available options

name	description	privileged	authored
/after_pull_request	Wait for the given pull request id to be merged before continuing with the current one.
/bypass_author_approval	Bypass the pull request author's approval	⭐
/bypass_build_status	Bypass the build and test status	⭐
/bypass_commit_size	Bypass the check on the size of the changeset TBA	⭐
/bypass_incompatible_branch	Bypass the check on the source branch prefix	⭐
/bypass_jira_check	Bypass the Jira issue check	⭐
/bypass_peer_approval	Bypass the pull request peers' approval	⭐
/bypass_leader_approval	Bypass the pull request leaders' approval	⭐
/approve	Instruct Bert-E that the author has approved the pull request.		✍️
/create_pull_requests	Allow the creation of integration pull requests.
/create_integration_branches	Allow the creation of integration branches.
/no_octopus	Prevent Wall-E from doing any octopus merge and use multiple consecutive merge instead
/unanimity	Change review acceptance criteria from one reviewer at least to all reviewers
/wait	Instruct Bert-E not to run until further notice.

Available commands

name	description	privileged
/help	Print Bert-E's manual in the pull request.
/status	Print Bert-E's current status in the pull request TBA
/clear	Remove all comments from Bert-E from the history TBA
/retry	Re-start a fresh build TBA
/build	Re-start a fresh build TBA
/force_reset	Delete integration branches & pull requests, and restart merge process from the beginning.
/reset	Try to remove integration branches unless there are commits on them which do not appear on the source branch.

Status report is not available.

[bert-e]

Waiting for approval

The following approvals are needed before I can proceed with the merge:

• the author

• one peer

Peer approvals must include at least 1 approval from the following list:

• @JBWatenbergScality

• @MonPote

• @damiengillesscality

• @ZiyangLinScality

• @JeanMarcMilletScality

• @hervedombya

• @ChengYanJin

[ChengYanJin]

LGTM