Fix UnboundLocalError when no faces are detected

[Mr-Neutr0n]

Summary

• Initialize mask_sharp before the face detection loop to prevent UnboundLocalError when no faces are detected

Problem

When processing an image/frame with no detected faces, the code crashes with:

UnboundLocalError: local variable 'mask_sharp' referenced before assignment

This happens because mask_sharp is only assigned inside the for loop (line 93), but is used after the loop (line 113). If the loop never executes (no faces detected), the variable is undefined.

Solution

Initialize mask_sharp with zeros before the loop, matching the dimensions of full_mask.

Test plan

• Process an image with no faces and verify no crash occurs
• Process an image with faces and verify output is unchanged

Fixes #273

[Mr-Neutr0n]

following up on this. fixes an UnboundLocalError crash when no faces are detected in a frame — the variable was used before assignment. small fix