feat: implement variable team matchups with partner rotation

- Add manual team entry for permanent teams in Matchups tab
- Rename 'Teams' tab to 'Matchups' for clarity
- Implement partner rotation strategies (minimize_repeat, maximize_even, elo_based)
- Track partnerships across rounds to minimize repeat pairings
- Fix unit tests for team configuration and ELO calculations
- Add E2E test for 9+ participant tournaments with variable matchups

Key changes:
- TeamsSection.tsx: Added router.refresh(), manual team entry, and matchup display
- schedule-generator.ts: Enhanced generateVariableRoundRobin to track partnerships
- team-generator.ts: Fixed partnership frequency tracking across rounds
- API routes: Updated to support variable team durability with rotation strategies

src/lib/elo-utils.ts

@@ -229,13 +229,18 @@ export async function recalculateAllElo(prisma: PrismaClient) {
   };
 
   // Process each match in chronological order
+  console.log('recalculateAllElo: Starting match processing loop');
   for (const match of matches) {
+    console.log('recalculateAllElo: Processing match', match.id);
     const { player1P1, player1P2, player2P1, player2P2, team1Score, team2Score, id: matchId, playedAt } = match;
 
     // Skip matches with missing players
     if (!player1P1 || !player1P2 || !player2P1 || !player2P2) {
+      console.log('recalculateAllElo: Skipping match due to missing players');
       continue;
     }
+    
+    console.log('recalculateAllElo: Match has all players, processing...');
 
     // Get current ratings for all players
     const p1Rating = getPlayerStats(player1P1.id).rating;