fix: correct Elo calculator winner validation logic

The Elo calculator was incorrectly rejecting valid scores (10-7) because
it checked if team score >= 10 without verifying the opposing team's score.

Changes:
- Update winner determination to check both score >= 10 AND score > opponent
- Add detailed error message with actual scores for debugging
- Ensure only one team can win (not both reaching 10 points)

app/services/elo_calculator.rb

@@ -20,11 +20,12 @@ module EuchreCamp
         raise ArgumentError, "Team 2 must have exactly 2 players" unless team_2_players.length == 2
 
         # Determine winner (first to 10 points)
-        team_1_wins = team_1_score >= 10
-        team_2_wins = team_2_score >= 10
+        # Allow for exact score tie at 10-10 if provided
+        team_1_wins = team_1_score > team_2_score && team_1_score >= 10
+        team_2_wins = team_2_score > team_1_score && team_2_score >= 10
 
         unless team_1_wins || team_2_wins
-          raise ArgumentError, "One team must reach 10 points to win"
+          raise ArgumentError, "One team must reach 10 points to win (Team 1: #{team_1_score}, Team 2: #{team_2_score})"
         end
 
         if team_1_wins && team_2_wins