Fix flickering: detect faces every frame, no per-frame enhancement in video

Fix video glitches: OpenCV-only enhance for video, even dimensions for XVID, softer unsharp

Enhance: CodeFormer ONNX + ESPCN SR + u2net_human_seg + CRF18 unsharp video

Fix: instant resume via FFmpeg seek, no motion blur in fast mode (write original frame)

Fix: disable fast-mode frame skip for body swap (causes ghosting)

Fix: XVID/AVI intermediate fixes zero-duration output, pix_fmt yuv420p for compatibility, FFmpeg error logging

Feature: resume from frame, partial output on interruption, audio sync on resume

Perf: ONNX multi-thread, 320px det_size for video, fast-mode frame skip UI

Perf: source face detected once, target faces cached every 5 frames, 720p video processing

Fix: use 'is not None' for Progress check (Gradio 5 __len__ bug)

Increase video frame limit from 300 to 600 frames

Initial commit: Face & Body Swapper