TEC-2722 — PATCH /api/v1/auth/profile now accepts phoneNumber alongside
fullName, avatarUrl, and email. Phone changes are deferred until the user
confirms the SMS OTP via POST /api/v1/auth/profile/verify-phone, mirroring
the existing email-change OTP flow.
- Add PhoneChangeRequestedEvent + user.phone_change_otp SMS template
- Add VerifyPhoneChangeHandler with Redis-backed 10-minute OTP
- Re-check phone uniqueness at verify time to catch races
- Extend unit tests for UpdateProfileHandler + add VerifyPhoneChangeHandler spec
Co-Authored-By: Paperclip <noreply@paperclip.ing>