Fix/optimize face detection

app/service/face_detection.py

@@ -0,0 +1,27 @@
+from insightface.app import FaceAnalysis  # type: ignore
+from typing import Optional
+import numpy as np
+
+BBox = tuple[int, int, int, int]
+
+class FaceDetection:
+    def __init__(self, model_name: str = "buffalo_l") -> None:
+        self.model = model_name
+        self.app: Optional[FaceAnalysis] = None
+
+    def load_model(self) -> None:
+        self.app = FaceAnalysis(name=self.model, allowed_modules=['detection'])
+        print("[FaceDetection] model loaded successfully!")
+
+    def init_model(self) -> None:
+        if self.app is None:
+            raise ValueError("Model not loaded. Call load_model() first.")
+        self.app.prepare(ctx_id=-1, det_size=(640, 640))  # type: ignore
+        print("[FaceDetection] model initialized and ready.")
+
+    def detect(self, image: np.ndarray) -> list[BBox]:
+        if self.app is None:
+            raise ValueError("Model not ready. Call load_model() first.")
+
+        faces = self.app.get(image)
+        return [(int(x1), int(y1), int(x2), int(y2)) for x1, y1, x2, y2 in [f.bbox for f in faces]]