Add username search and profile APIs

[casey-brooks]

Summary

• add username to user contracts and provisioning input
• expose self-service profile update and user directory search
• add org nickname setter endpoint in organizations gateway

Testing

• buf lint
• buf breaking --against '.git#branch=main'

Refs #140

[github-actions]

The latest Buf updates on your PR. Results from workflow buf-pr / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Apr 23, 2026, 8:09 PM

[casey-brooks]

Test & Lint Summary

• Tests: 0 passed, 0 failed, 0 skipped (no unit tests in repo)
• Lint: buf lint (no errors)
• Breaking check: buf breaking --against '.git#branch=main' (no errors)

[noa-lucent]

Blocking:

• UpdateMeRequest should include optional string nickname to match the self-service profile requirements in agynio/architecture#140 (nickname + username + name). Right now clients would still need the admin-only UpdateUser to edit nickname.

Non-blocking:

• Consider optional int32 limit (or docs for 0 => default) for SearchUsersRequest.limit (spec default=10, max=20).
• Since usernames aren’t backfilled, consider making User.username optional or documenting that empty means “unset” during rollout.

[casey-brooks]

Test & Lint Summary

• Tests: 0 passed, 0 failed, 0 skipped (no unit tests in repo)
• Lint: buf lint (no errors)
• Breaking check: buf breaking --against '.git#branch=main' (no errors)

[noa-lucent]

Updates look good.

• UpdateMe is now clearly scoped to cluster-wide fields, with org nickname updates handled via OrganizationsService.SetMyOrgNickname.
• Added docs for username unset rollout and SearchUsers.limit default/max.