리노컷 자산 파이프라인 공통화와 캐스트 외형 설계

- P1 전용 스크립트를 docs/avatar-art/linocut-pipeline 으로 옮겨 persona.json 설정으로 일반화(P1 재실행 리그 바이트 동일)
- 7명 외형·상징 설계(linocut-cast.md)와 P2~P7 정면 원화 생성 프롬프트, 얼굴 없는 화풍 참조
- P1 원화 생성 프롬프트 보존

docs/avatar-art/p1-linocut/prompts/base-faceless.txt

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+Call the built-in image_gen tool immediately, using the attached image as the reference to edit. Do not read any files, do not use any skill, do not ask questions. Invoke the image_gen tool once with size 1024x1536 and high quality, using exactly this prompt, then save the resulting image into the current directory as b2-faceless.png:
+
+Redraw exactly the same girl, same frontal pose, same framing and same linocut relief-print style as the reference, but leave the face blank: remove the eyes, eyebrows and mouth completely and fill those areas with plain skin in the same flat skin color, keeping the nose, the face outline, the ears, the hair, the neck and the hoodie exactly as they are. Plain flat cream background, nothing else, no text.

docs/avatar-art/p1-linocut/prompts/base-front.txt

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+Call the built-in image_gen tool immediately, using the attached image as the reference to edit. Do not read any files, do not use any skill, do not ask questions. Invoke the image_gen tool once with size 1024x1536 and high quality, using exactly this prompt, then save the resulting image into the current directory as b1-front-neutral.png:
+
+Redraw the same girl from the reference in exactly the same linocut relief-print style, same face, same hair, same charcoal hoodie and white t-shirt, same ink colors and paper. Change only the pose: head and body facing the viewer straight on (frontal, symmetrical), neutral closed mouth, eyes open looking straight at the viewer, shoulders level. Head, neck and shoulders only, hands out of frame. The figure is centered on a plain flat cream background with nothing else: no flowers, no clouds, no motifs, no text.