Fix tenant-scoped team membership test setup

[alejandro-runner]

Summary

• create the missing tenant row in the tenant-scoped team membership repository test
• fix CI failure introduced by the first-team creation change

Why

The test inserted a team with tenant_id = 2 without creating tenant 2, which violates the teams_tenant_id_fkey constraint in CI.

Verification

• targeted keycast_core integration test setup reviewed
• local feature-gated test execution in this sandbox is blocked by localhost DB permissions