Fix scheduler warning: use last_epoch instead of step() loop on resume

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/training/train_gtauav.py

@@ -331,9 +331,8 @@ def train(cfg: TrainConfigGTAUAV) -> None:
         if "loss_state" in resume_ckpt:
             loss_fn.load_state_dict(resume_ckpt["loss_state"])
             LOGGER.info("🔄 Loss state restored (tau=%.4f)", loss_fn.current_temperature)
-        # Advance scheduler to the correct step.
-        for _ in range(start_epoch * steps_per_epoch):
-            scheduler.step()
+        # Set scheduler last_epoch so it resumes at the correct LR.
+        scheduler.last_epoch = start_epoch * steps_per_epoch
         LOGGER.info("🔄 Resuming from epoch %d", start_epoch)
 
     history: list[dict] = []