normalize email addresses

Author: Thomas Stromberg

internal/notify/daily_test.go

@@ -36,8 +36,8 @@ func TestFormatDigestMessage(t *testing.T) {
 _Your daily digest from Ready to Review_`,
 		},
 		{
-			name: "outgoing PRs only at 8:15am",
-			time: time.Date(2025, 10, 22, 8, 15, 0, 0, time.UTC),
+			name:     "outgoing PRs only at 8:15am",
+			time:     time.Date(2025, 10, 22, 8, 15, 0, 0, time.UTC),
 			incoming: nil,
 			outgoing: []home.PR{
 				{

internal/usermapping/usermapping.go

@@ -387,7 +387,9 @@ func (s *Service) findSlackMatches(ctx context.Context, githubUsername string, e
 
 	// Search for each email in Slack user directory
 	for _, email := range emails {
-		user, err := s.slackClient.GetUserByEmailContext(ctx, email)
+		// Normalize email to lowercase for consistent matching
+		normalizedEmail := strings.ToLower(email)
+		user, err := s.slackClient.GetUserByEmailContext(ctx, normalizedEmail)
 		if err != nil {
 			slog.Debug("no Slack user found for email",
 				"email", email,