v0.6.10: protect text and CJK glyphs during removal

v0.6.10: protect text and CJK glyphs during removal

Highlight: automatic text protection (#21)

The SDXL img2img pass could deform text, especially Chinese and other CJK
glyphs, at watermark removal strengths. The SDXL pipeline now guards against
this automatically: a CJK native PP-OCRv3 detector (2.4 MB ONNX, cv2.dnn, no
torch) locates text regions, and when any are found the pass switches to
Differential Diffusion so the text pixels are preserved while the rest of the
image is still scrubbed. Text-free images run the standard pass at no extra
cost. Pass --no-protect-text to turn it off.

Also since v0.6.5

• Require transformers 5.x with a stable tokenizers pin so SDXL loads again.
• Integrity clash detection for contradictory provenance signals (v0.6.7).
• Detect C2PA/AIGC/IPTC manifests placed after a large mdat in MP4 (v0.6.8).
• Blank an AI label XMP packet stored inside the HEIF/AVIF meta box (v0.6.9).
• Unicode safe cv2 image IO and a fixed [gpu] install hint (v0.6.6).