feat: enable retinaface detector, download retinaface.h5 from HF Hub during build

app/utils/ml_engine.py

@@ -8,7 +8,7 @@ import time
 logger = logging.getLogger(__name__)
 
 class FaceAnalyzer:
-    def __init__(self, detector_backend='opencv'):
+    def __init__(self, detector_backend='retinaface'):
         """
         Face recognition and analysis engine using DeepFace.
         'opencv' is used for lightweight deployment (avoids OOM on HF Spaces).

scripts/build_models.py

@@ -17,6 +17,7 @@ MODEL_FILES = [
     "gender_model_weights.h5",
     "facial_expression_model_weights.h5",
     "race_model_single_batch.h5",
+    "retinaface.h5",
 ]