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/repositories/teams.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require 'rom-repository'
+
+module EuchreCamp
+  module Repositories
+    class Teams < ::EuchreCamp::Repository[:teams]
+      commands :create, update: :by_pk, delete: :by_pk
+
+      def by_event(event_id)
+        teams.where(event_id: event_id).to_a
+      end
+
+      def find_or_create(event_id, player_1_id, player_2_id, team_name = nil)
+        existing = teams.where(
+          event_id: event_id,
+          player_1_id: [player_1_id, player_2_id],
+          player_2_id: [player_1_id, player_2_id]
+        ).one
+
+        return existing if existing
+
+        create(
+          event_id: event_id,
+          player_1_id: player_1_id,
+          player_2_id: player_2_id,
+          team_name: team_name || "Team #{player_1_id}-#{player_2_id}"
+        )
+      end
+    end
+  end
+end