Include both display name and username in password reset emails

As requested by @nitnelave, the password reset email now includes both the display name for personalization and the username for recovery. The email uses the display name in the greeting when available, but always shows the username explicitly for recovery purposes.

Co-authored-by: nitnelave <796633+nitnelave@users.noreply.github.com>

server/src/auth_service.rs

@@ -186,6 +186,7 @@ where
         Some(token) => token,
     };
     if let Err(e) = super::mail::send_password_reset_email(
+        user.display_name.as_deref(),
         user.user_id.as_str(),
         user.email.as_str(),
         &token,

server/src/mail.rs

@@ -80,6 +80,7 @@ async fn send_email(
 }
 
 pub async fn send_password_reset_email(
+    display_name: Option<&str>,
     username: &str,
     to: &str,
     token: &str,
@@ -92,8 +93,14 @@ pub async fn send_password_reset_email(
         .path_segments_mut()
         .unwrap()
         .extend(["reset-password", "step2", token]);
+    
+    let greeting = match display_name {
+        Some(name) if !name.is_empty() => format!("Hello {name},"),
+        _ => "Hello,".to_string(),
+    };
+    
     let body = format!(
-        "Hello,
+        "{greeting}
 This email has been sent to you in order to validate your identity.
 If you did not initiate the process your credentials might have been
 compromised. You should reset your password and contact an administrator.