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/actions/admin/tournaments/complete.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Actions
+    module Admin
+      module Tournaments
+        class Complete < EuchreCamp::Action
+          include Deps[events_repo: 'repositories.events']
+
+          def handle(request, response)
+            tournament_id = request.params[:id]
+
+            events_repo.update(tournament_id, status: 'completed')
+
+            response.flash[:message] = "Tournament completed"
+            response.redirect_to("/admin/tournaments/#{tournament_id}")
+          rescue StandardError => e
+            response.flash[:error] = "Failed to complete tournament: #{e.message}"
+            response.redirect_to("/admin/tournaments/#{tournament_id}")
+          end
+        end
+      end
+    end
+  end
+end