feat: enhance match entry form with validation and data

Add improved match entry form with player selection validation and
better user experience for recording match results.

Changes:
- Add player validation to prevent same player on both teams
- Add team score validation (must have winner)
- Improve form layout and player selection UI
- Add helper methods for player lookup and team building

app/views/admin/matches/new.rb

@@ -6,6 +6,10 @@ module EuchreCamp
       module Matches
         class New < EuchreCamp::View
           expose :players
+          expose :tournament
+          expose :teams
+          expose :preselected_team_1
+          expose :preselected_team_2
         end
       end
     end