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/20240915000005_create_tournament_rounds.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+ROM::SQL.migration do
+  change do
+    create_table :tournament_rounds do
+      primary_key :id
+      foreign_key :event_id, :events, null: false
+      column :round_number, Integer, null: false
+      column :status, String, default: 'pending'  # pending, active, completed
+      column :scheduled_start, DateTime
+      column :actual_start, DateTime
+      column :completed_at, DateTime
+    end
+
+    add_index :tournament_rounds, [:event_id, :round_number], unique: true
+  end
+end