feat(tournaments): add partnership tracking and tournament management

Implement comprehensive partnership tracking system and tournament
management features including round-robin, single/double elimination,
and Swiss system pairings.

Changes:
- Add partnership_games and partnership_stats tables
- Implement PartnershipTracker service for recording partnership data
- Add tournament generator with multiple formats
- Create tournament management actions and views
- Add acceptance tests for partnership tracking
- Fix PartnershipTracker to use single snapshot per player per match
- Fix round-robin test to query by round_number instead of hardcoded ID

Note: All 8 acceptance tests now passing

app/views/admin/tournaments/show.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Views
+    module Admin
+      module Tournaments
+        class Show < EuchreCamp::View
+          expose :tournament
+          expose :players
+          expose :available_players
+          expose :teams
+          expose :rounds
+          expose :participants
+        end
+      end
+    end
+  end
+end