fix(seed): add missing Host entries for seeded round‑robin and collective team events

[abhayymishraa]

What does this PR do?

This PR fixes the problem where round‑robin (and collective) team event types seeded in development did not display any team availabilities. The root cause was that the seeding logic created the team and its members but never created the corresponding Host records that link users to the event type. Without those Host entries the availability engine has no users to query, so the UI shows an empty slot list.

• Fixes Round robin events seeded in development do not display team availabilities #25226
• Fixes CAL-6773

Visual Demo (For contributors especially)

A visual demonstration is strongly recommended, for both the original and new change (video / image - any one).

Video Demo (if applicable):

After fix:

Screen.Recording.2026-01-04.at.2.02.34.PM.mov

Mandatory Tasks (DO NOT REMOVE)

• I have self-reviewed the code (A decent size PR without self-review might be rejected).
• I have updated the developer docs in /docs if this PR makes changes that would require a documentation change. If N/A, write N/A here and check the checkbox.
• I confirm automated tests are in place that prove my fix is effective or that my feature works.

How should this be tested?

1. Reset the DB (as you already did):

   yarn workspace @calcom/prisma db-reset

2. Run the seed script:

   yarn dx   # or the command you normally use to seed

3. Log in as [email protected] (or any seeded user that belongs to a team with a round‑robin event).
4. Navigate to Team → Seeded Team → “Round Robin Seeded Team Event”.
5. Verify that the calendar now shows the team members’ available time slots (instead of an empty list).

Environment variables: No special env vars are needed beyond the usual ones for the local dev server.

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• Are there environment variables that should be set?
• What are the minimal test data to have?
• What is expected (happy path) to have (input and output)?
• Any other important info that could help to test that PR

Checklist

[vercel]

@abhayymishraa is attempting to deploy a commit to the cal Team on Vercel.

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[cubic-dev-ai]

No issues found across 1 file

[dhairyashiil]

LGTM