Summary of changes

Updated the assignment flow to support inviting people by email.

If an email does not belong to an existing team member, the user is automatically invited to the team as a Member.

Added support for multiple emails, using comma-separated input (user1@example.com, user2@example.com).

Updated frontend and backend to handle new host format { email, isPending } in addition to { userId }.

Why this is useful

Makes it easier to quickly assign event-types to new collaborators without requiring them to be manually added to the team first.

Supports inviting multiple participants in a single step, improving workflow efficiency.

Notes

This PR only covers the basic invitation + assignment flow. CI should validate tests, but feedback on edge cases (e.g., invalid emails, already invited users) would be appreciated.

Bounty

/claim https://github.com/calcom/cal.com/issues/13532