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/templates/admin/tournaments/rounds/show.html.erb

@@ -0,0 +1,47 @@
+<h1><%= tournament.name %> - Round <%= round[:round_number] %></h1>
+
+<p><strong>Status:</strong> <%= round[:status] %></p>
+
+<h2>Matchups</h2>
+
+<% if matchups.any? %>
+  <table>
+    <thead>
+      <tr>
+        <th>Position</th>
+        <th>Team 1</th>
+        <th>vs</th>
+        <th>Team 2</th>
+        <th>Winner</th>
+        <th>Actions</th>
+      </tr>
+    </thead>
+    <tbody>
+      <% matchups.each do |matchup| %>
+        <% team_1 = teams.find { |t| t.id == matchup[:team_1_id] } %>
+        <% team_2 = teams.find { |t| t.id == matchup[:team_2_id] } %>
+        <% winner = teams.find { |t| t.id == matchup[:winner_team_id] } %>
+        <tr>
+          <td><%= matchup[:bracket_position] %></td>
+          <td><%= team_1&.team_name || 'BYE' %></td>
+          <td>vs</td>
+          <td><%= team_2&.team_name || 'BYE' %></td>
+          <td><%= winner&.team_name || '-' %></td>
+          <td>
+            <% if matchup[:match_id].nil? %>
+              <a href="/admin/matches/new?event_id=<%= tournament.id %>&team_1_id=<%= matchup[:team_1_id] %>&team_2_id=<%= matchup[:team_2_id] %>">
+                Create Match
+              </a>
+            <% else %>
+              <a href="/admin/matches/<%= matchup[:match_id] %>">View Match</a>
+            <% end %>
+          </td>
+        </tr>
+      <% end %>
+    </tbody>
+  </table>
+<% else %>
+  <p>No matchups scheduled for this round.</p>
+<% end %>
+
+<p><a href="/admin/tournaments/<%= tournament.id %>">Back to Tournament</a></p>