feat(SAC_LSTM_Bot): training harness (#49)

sac_train.sh orchestrates chunked self-play via tools/training_runner/
RunTraining.java: weighted opponent sampling per chunk, deterministic
eval (SACLSTM_EVAL_MODE=1) every N chunks with win-rate tracking, best
checkpoint (weights/sac_best.zip) by eval score, crash-restart loop on
the runner's liveness detection.

Supporting changes:
- integration.nim: opponentKey() keys the NewBattle buffer-clear rule on
  getBotName(id) with numeric-id fallback (#49 Q14 follow-up);
  bumpRoundCounter() emits the per-round liveness signal.
- SAC_LSTM_Bot.nim: onRoundEnded -> bumpRoundCounter().
- RunTraining.java: BOT_NAME env parameterizes result matching
  (default PPO_Bot, unchanged behavior for PPO).
- Launch packaging: root SAC_LSTM_Bot.json + .sh for the booter;
  src json name aligned to 'SAC_LSTM_Bot' so self-reported identity
  matches the booted identity (mismatch = runner connect timeout).

tools/training_runner/RunTraining.java

@@ -18,9 +18,10 @@ import java.util.logging.Logger;
  * to the same log file via PPOB_LOG_FILE — the shell wrapper stitches them.
  *
  * Usage (env vars):
- *   PPO_BOT_DIR      — path to PPO_Bot dir
+ *   PPO_BOT_DIR      — path to the bot dir (any Tank Royale bot)
  *   SAMPLE_BOTS_DIR  — path to sample bots archive
  *   PPOB_LOG_FILE    — path to training_log.jsonl (appended)
+ *   BOT_NAME         — bot name to match in round results (default: PPO_Bot)
  *   TRAINING_OPPONENT — opponent bot name (default: Target)
  *   TRAINING_ROUNDS  — number of rounds to run (CLI arg or env var)
  *
@@ -39,8 +40,9 @@ public class RunTraining {
             : System.getenv().getOrDefault("TRAINING_OPPONENT", "Target");
         int totalRounds = args.length > 1 ? Integer.parseInt(args[1])
             : Integer.parseInt(System.getenv().getOrDefault("TRAINING_ROUNDS", "100"));
+        String botName = System.getenv().getOrDefault("BOT_NAME", "PPO_Bot");
 
-        System.out.printf("Training: PPO_Bot vs %s for %d rounds%n", opponent, totalRounds);
+        System.out.printf("Training: %s vs %s for %d rounds%n", botName, opponent, totalRounds);
         System.out.printf("Log: %s%n", logFile);
 
         // Dead-bot guard: the runner keeps listing a crashed PPO_Bot in the
@@ -81,7 +83,7 @@ public class RunTraining {
                     boolean win = false;
                     boolean found = false;
                     for (var r : event.getResults()) {
-                        if (r.getName().equals("PPO_Bot")) {
+                        if (r.getName().equals(botName)) {
                             found = true;
                             totalScore = r.getTotalScore();
                             win = r.getRank() == 1;
@@ -99,9 +101,9 @@ public class RunTraining {
                         frozenRounds[0]++;
                         long frozenMs = System.currentTimeMillis() - lastAdvanceMs[0];
                         if (frozenRounds[0] >= 10 && frozenMs >= 10_000) {
-                            System.err.printf("PPO_Bot round_counter frozen at %d for %d "
+                            System.err.printf("%s round_counter frozen at %d for %d "
                                 + "harness rounds / %.0fs — process dead, aborting for restart%n",
-                                ctr, frozenRounds[0], frozenMs / 1000.0);
+                                botName, ctr, frozenRounds[0], frozenMs / 1000.0);
                             System.exit(1);
                         }
                     } else {
@@ -110,7 +112,7 @@ public class RunTraining {
                         lastAdvanceMs[0] = System.currentTimeMillis();
                     }
                     if (!found) {
-                        System.err.println("PPO_Bot missing from round " + round
+                        System.err.println(botName + " missing from round " + round
                             + " results — process died, aborting battle for restart");
                         System.exit(1);
                     }
@@ -147,10 +149,10 @@ public class RunTraining {
                     endCounter = readCounter(counterPath);
                 }
                 if (endCounter < expectedEnd) {
-                    System.err.printf("PPO_Bot round_counter %d < expected %d (start+%d) at battle "
+                    System.err.printf("%s round_counter %d < expected %d (start+%d) at battle "
                         + "end (waited 60s) — %d rounds never trained (corpse?), aborting for "
                         + "restart%n",
-                        endCounter, expectedEnd, totalRounds, expectedEnd - endCounter);
+                        botName, endCounter, expectedEnd, totalRounds, expectedEnd - endCounter);
                     System.exit(1);
                 }
                 System.out.printf("Counter check passed: %d == expected %d%n", endCounter, expectedEnd);