🚀 V3: MULTI-SEED ENSEMBLE + T0-ONLY + SELF-TRAINING
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Clean: (652, 24, 16, 16), 7 classes, [65, 52, 48, 72, 108, 219, 88]

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MULTI-SEED CNN ENSEMBLE (10 models)
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  Seed 0: 0.8473
  Seed 1: 0.8702
  Seed 2: 0.8550
  Seed 3: 0.8550
  Seed 4: 0.8702
  Seed 5: 0.8626
  Seed 6: 0.8702
  Seed 7: 0.8702
  Seed 8: 0.8702
  Seed 9: 0.8702
  ✅ 10-Model Ensemble TTA: 0.8473

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TIMESTEP-0-ONLY XGBoost (cleanest data)
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  T0 valid: 539/652
  Features: (539, 1638)
  XGB t0: 0.6852
  LGBM t0: 0.6296
  ET t0: 0.6852