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

db/migrate/20240915000006_create_bracket_matchups.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+ROM::SQL.migration do
+  change do
+    create_table :bracket_matchups do
+      primary_key :id
+      foreign_key :event_id, :events, null: false
+      foreign_key :round_id, :tournament_rounds, null: false
+      foreign_key :match_id, :matches
+      foreign_key :team_1_id, :teams
+      foreign_key :team_2_id, :teams
+      column :bracket_position, Integer
+      column :winner_team_id, Integer
+      column :loser_team_id, Integer
+    end
+
+    add_index :bracket_matchups, [:event_id, :round_id, :bracket_position], unique: true
+  end
+end