fix: change image encoding from RGBA to JPEG for improved performance and reduced size

app.py

@@ -959,9 +959,9 @@ def build_segmentation_bundle(contents: bytes):
     print(f"[TIMING] Floor segmentation took {time.perf_counter() - t0:.3f} seconds", flush=True)
 
     t0 = time.perf_counter()
-    rgba = np.dstack([img_np, np.full((h, w), 255, dtype=np.uint8)])
-    pixels_b64 = base64.b64encode(rgba.tobytes()).decode()
-    print(f"[TIMING] Image RGBA encoding took {time.perf_counter() - t0:.3f} seconds", flush=True)
+    success, jpeg_buf = cv2.imencode(".jpg", cv2.cvtColor(img_np, cv2.COLOR_RGB2BGR), [cv2.IMWRITE_JPEG_QUALITY, 90])
+    pixels_b64 = base64.b64encode(jpeg_buf.tobytes()).decode()
+    print(f"[TIMING] Image JPEG encoding took {time.perf_counter() - t0:.3f} seconds", flush=True)
 
     t0 = time.perf_counter()
     primary_floor_ids = class_ids(PRIMARY_FLOOR_CLASSES)