Fix uint8 overflow in LSB steganography embedding

- Convert numpy uint8 to Python int before bitwise operations
- Mask result with 0xFF and explicitly cast back to uint8
- Fixes 'Python integer -2 out of bounds for uint8' error
- Ensures pixel values stay in valid 0-255 range

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

steg_embedder.py

@@ -152,7 +152,8 @@ class StegEmbedder:
                     break
 
                 # Clear LSBs and set new bits
-                pixel = flat_array[i]
+                # Convert to Python int to avoid numpy uint8 overflow issues
+                pixel = int(flat_array[i])
                 for bit in range(bits_per_channel):
                     if bit_index >= len(bit_string):
                         break
@@ -163,7 +164,8 @@ class StegEmbedder:
                         pixel = pixel | (1 << bit)
                     bit_index += 1
 
-                flat_array[i] = pixel
+                # Ensure result stays within uint8 range (0-255)
+                flat_array[i] = np.uint8(pixel & 0xFF)
 
             # Reshape and save
             steg_img_array = flat_array.reshape(img_array.shape)