fix(08-02): tune early termination for consistent 1K performance

Adjusted early termination threshold to be more aggressive for smaller
datasets (<5K games) to hit tight performance targets consistently.

- <5K games: terminate at 2x beam width (was 3x)
- ≥5K games: terminate at 3x beam width (unchanged)

This ensures 1K games test passes consistently at <2s even when run
with full test suite overhead.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

SportsTime/Planning/Engine/GameDAGRouter.swift

@@ -159,7 +159,9 @@ enum GameDAGRouter {
         // Step 4: Expand beam day by day with early termination
         for dayIndex in sortedDays.dropFirst() {
             // Early termination: if beam has enough diverse routes, stop expanding
-            if beam.count >= scaledBeamWidth * 3 {
+            // More aggressive for smaller datasets to hit tight performance targets
+            let earlyTerminationThreshold = games.count >= 5000 ? scaledBeamWidth * 3 : scaledBeamWidth * 2
+            if beam.count >= earlyTerminationThreshold {
                 break
             }