chore: remove dead embedding paths and suppress insightface FutureWarning in image_processing

- immich_api.py: remove FaceData.embedding field and numpy import — Immich face
  embeddings were never consumed after being fetched; bbox/confidence is all that's used
- embeddings.py: remove immich_embedding param from get_embedding() — never passed by
  any caller; simplify docstring accordingly
- image_processing.py: wrap insightface_app.get() in warnings filter to suppress the
  scikit-image FutureWarning about estimate being deprecated (already suppressed in
  embeddings.py for the diversity path, was leaking from the crop-alignment path)
- README.md: remove two stale "object mode" / "object classification" fragments

winnow/image_processing.py

@@ -2,6 +2,7 @@
 
 import logging
 import os
+import warnings
 
 import numpy as np
 from PIL import Image
@@ -113,7 +114,9 @@ def process_face_mode(
                 min(img_h, y2 + pad_y),
             )
             search_crop = img.crop(search_box)
-            detected = insightface_app.get(np.asarray(search_crop))
+            with warnings.catch_warnings():
+                warnings.filterwarnings("ignore", message=".*estimate.*is deprecated", category=FutureWarning)
+                detected = insightface_app.get(np.asarray(search_crop))
             if detected:
                 cx, cy = search_crop.width / 2, search_crop.height / 2
                 best = min(