Allow optional uid in Google seed config to stabilize sub claim across restarts

[ikad]

Summary

• Add optional uid field to GoogleSeedUser interface
• Use the provided uid when seeding users, falling back to generateUid("goog") if omitted

Problem

When running the Google emulator in Docker or any environment where the process restarts, the sub claim in id_tokens changes on every restart because uid is always generated randomly. Applications that store users by their sub value treat the same person as a different user after each restart.

Solution

Follow the same pattern already established by the Okta emulator (okta_id?: string with user.okta_id ?? generateOktaId("00u")), allowing operators to pin a stable uid in their seed configuration:

seedFromConfig(store, base, {
  users: [
    { email: "alice@example.com", uid: "goog_stable_uid_alice" }
  ]
})

When uid is omitted the behavior is unchanged — a random ID is generated as before.

[vercel]

@ikad is attempting to deploy a commit to the Vercel Labs Team on Vercel.

A member of the Team first needs to authorize it.