feat(SNNBot): add bullet economy test against WallsBot

Add --max-speed flag to TestBattleRunner (sets defaultTurnsPerSecond=-1 for unlimited TPS).
Add SNNBot_garage/tests/test_bullet_economy.nim: 10-round vs WallsBot, prints per-round and summary stats for tuning.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tools/battle_runner/TestBattleRunner.java

@@ -19,6 +19,7 @@ public class TestBattleRunner {
 
         String serverUrl = null;
         int rounds = 1;
+        boolean maxSpeed = false;
         List<String> botDirs = List.of();
 
         for (int i = 0; i < args.length; i++) {
@@ -26,6 +27,7 @@ public class TestBattleRunner {
                 case "--server-url" -> serverUrl = args[++i];
                 case "--rounds"     -> rounds = Integer.parseInt(args[++i]);
                 case "--bot-dirs"   -> botDirs = Arrays.asList(args[++i].split(","));
+                case "--max-speed"  -> maxSpeed = true;
                 default -> { System.err.println("Unknown arg: " + args[i]); System.exit(1); }
             }
         }
@@ -36,7 +38,12 @@ public class TestBattleRunner {
         final String url = serverUrl;
         final List<BotEntry> bots = botDirs.stream().map(BotEntry::of).collect(Collectors.toList());
         final int numRounds = rounds;
-        final var setup = BattleSetup.classic(s -> s.setNumberOfRounds(numRounds));
+        final boolean runMaxSpeed = maxSpeed;
+        // -1 = max TPS (no speed limit); see ServerCli.kt: "where -1 means maximum TPS"
+        final var setup = BattleSetup.classic(s -> {
+            s.setNumberOfRounds(numRounds);
+            if (runMaxSpeed) s.setDefaultTurnsPerSecond(-1);
+        });
 
         // Debug: check what JSON files the runner will find for each bot dir
         for (String dir : botDirs) {