LDAP user lookup fails due to email case mismatch

[quentinovega]

Description

When adding a user to a team, the system checks if the user already exists in the database. If found via LDAP, a temporary user is created and invited. However, LDAP may return emails with mixed or uppercase characters (e.g. John.Doe@Company.com), and these are stored as-is in the database.

Later, when looking up the user via findUserByAttributes (TeamController.scala L1045), the query uses a case-sensitive match, so it fails to find the user if the stored email differs in case from the search input.

Steps to reproduce

1. A user is created from LDAP with email John.Doe@Company.com
2. Try to add this user to a team by searching for john.doe@company.com
3. findUserByAttributes returns null — user not found

Proposed fix

1. Normalize emails to lowercase on write — Whenever an email is stored (user creation, LDAP sync, etc.), convert it to lowercase first. Per RFC 5321, the local part of an email can be case-sensitive in theory, but in practice no major provider enforces this, and lowercase normalization is the industry standard.
2. Make findUserByAttributes case-insensitive — Use a case-insensitive comparison (e.g. LOWER() / ILIKE in PostgreSQL) for email lookups, so existing data with mixed case is still matched correctly.