## What does this PR do?
This PR is stacked on https://github.com/calcom/cal.com/pull/24299 this adds the v3 flow for onboarding with teams.
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## Summary by cubic
Adds the v3 team onboarding flow with Details, Brand, and Invite steps, including slug validation, branding, and member invites. Updates routing to support the Team plan and creates teams with Stripe checkout when needed.
- **New Features**
- Team Details: name and slug with async availability check and URL preview.
- Team Brand: hex color picker and logo upload with live preview.
- Team Invite: add/remove emails, invite role toggle (Member/Admin), and form validation.
- State: adds teamDetails, teamBrand, and teamInvites to the onboarding store with actions.
- Creation: new useCreateTeam hook; redirects to Stripe if checkout URL is returned, or to Getting Started on success.
- Routing/Auth: protected team pages (details, brand, invite) and updates plan selection to route to /onboarding/teams.
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