fix(botapi): static event queue storage + end-of-battle train wait

The event queue's heap seq was the last GC'd block surviving across
rounds: each round runs on a freshly spawned bot thread, so the N+1
thread realloc'd a block grown by dead thread N's allocator mid-round
(at the next capacity doubling, ~turn 104) -> rawDealloc SIGSEGV in
addEvent (7 gdb-confirmed coredumps). Replace with a static
array[MAX_QUEUE_SIZE, BotEvent] + eventsLen: no heap block crosses
threads, realloc can never happen.

Also fix the harness aborting the final round mid-train: PPO_Bot's
onRoundEnded trains synchronously after the runner's RoundEndedEvent,
so the counter read right after awaitResults() is the stale pre-train
value and System.exit killed the bot inside ppoUpdate. Poll up to 60s
for the counter to catch up before declaring the battle incomplete.

Verified: 72 consecutive rounds vs Fire, 100% wins, all rounds trained
(counter advanced 1:1), zero coredumps since the fix.

tools/training_runner/training.env

@@ -0,0 +1,16 @@
+TRAINING_OPPONENT=Fire
+TRAINING_ROUNDS=3000
+PPOB_LOG_FILE=/home/davide/Projects/SirRoboGarage/tools/training_runner/logs/fire_training.jsonl
+PPOB_LR=0.0003
+PPOB_CLIP_EPSILON=0.2
+PPOB_ENTROPY_COEFF=0.01
+PPOB_VALUE_LOSS_COEFF=0.5
+PPOB_MAX_GRAD_NORM=0.5
+PPOB_GAMMA=0.99
+PPOB_LAM=0.95
+PPOB_EPOCHS=4
+PPOB_MINI_BATCH_SIZE=64
+PPOB_LOG_STD_FLOOR=-3.0
+PPOB_INITIAL_LOG_STD=0.0
+
+# PPOB_EVAL_ONLY=1 → freeze training (pure evaluation)