Add image extraction functionality with background removal

- Implemented ExtractImageRegion operator for extracting image regions using box or lasso selection.
- Added RemoveImageRegionBackground job for background removal from selected image regions.
- Created utility functions for polygon bounds, selection canvas creation, and applying selection masks.
- Integrated image processing using PIL and numpy for efficient pixel manipulation.
- Enhanced user experience with modal drawing and status updates during extraction.

tests/test_server.py

@@ -220,7 +220,7 @@ class ServerTest(unittest.TestCase):
                 "download-model",
                 "download-required-models",
                 "analyze-balloon",
-                "analyze-image-lasso",
+                "extract-image-background",
                 "remove-background",
                 "extract-frames",
                 "generate-depth",
@@ -401,16 +401,16 @@ class ServerTest(unittest.TestCase):
         self.assertEqual(tuple(result[0, 0]), (20, 40, 60, 64))
         self.assertEqual(tuple(result[3, 3]), (0, 0, 0, 0))
 
-    def test_image_lasso_canvas_clears_rgba_outside_the_selection(self):
+    def test_image_extract_canvas_clears_rgba_outside_the_selection(self):
         import numpy as np
         from PIL import Image
 
-        image_lasso = sys.modules["server.jobs.image_lasso"]
+        image_extract = sys.modules["server.jobs.image_extract"]
         source_path = self.storage_root / "source.png"
         pixels = np.full((2, 2, 4), (20, 40, 60, 255), dtype=np.uint8)
         Image.fromarray(pixels, mode="RGBA").save(source_path)
 
-        canvas, _selection, bounds = image_lasso.create_lasso_canvas(
+        canvas, _selection, bounds = image_extract.create_selection_canvas(
             source_path,
             ((-1, -1), (2, -1), (-1, 2)),
         )
@@ -421,14 +421,14 @@ class ServerTest(unittest.TestCase):
         self.assertEqual(tuple(result[2, 2]), (0, 0, 0, 0))
         self.assertEqual(tuple(result[1, 1]), (20, 40, 60, 255))
 
-    def test_image_lasso_crops_to_alpha_with_pixel_padding(self):
+    def test_image_extract_crops_to_alpha_with_pixel_padding(self):
         import numpy as np
         from PIL import Image
 
-        image_lasso = sys.modules["server.jobs.image_lasso"]
+        image_extract = sys.modules["server.jobs.image_extract"]
         pixels = np.zeros((4, 5, 4), dtype=np.uint8)
         pixels[1:3, 2:4] = (20, 40, 60, 255)
-        result, bounds = image_lasso.crop_to_alpha(
+        result, bounds = image_extract.crop_to_alpha(
             Image.fromarray(pixels, mode="RGBA"),
             (10, 20, 15, 24),
             padding=1,