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/linocut-cast-prompts/P6-front.txt

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+A Korean high-school senior girl of eighteen, intelligent and articulate but worn out, torn between what her parents want and what she loves. A thoughtful face with shadows of sleepless nights under her eyes and slightly chapped lips. Medium-length dark brown hair with a soft natural wave, the top half loosely held back with a plain hair claw clip (no decoration), a few strands falling loose beside her face (not over her eyes or eyebrows). She wears an oversized off-white cable-knit cardigan over a grey-and-white striped shirt, with a faint smudge of charcoal drawing dust on the edge of the cardigan collar. Her shoulders are drawn slightly inward.
+
+She must look like one specific real person, not a generic attractive person. Natural, realistic Korean facial features: eyes of natural human size (not enlarged), a slightly uneven face, a real nose and lips, natural skin texture. Eyes, eyebrows and mouth are fully visible: no hair, hands or objects over them, and no glasses. Dignified and deeply human. Strictly NOT anime, NOT manga, NOT webtoon, NOT K-pop idol styling, no big shiny eyes, no eyelash emphasis, no glamour. No marks or wounds on the skin.
+
+Draw a completely different person from the one in the reference image. Keep exactly the same linocut relief-print style as the reference: bold carved black-indigo lines with visible gouge marks, flat areas of only two additional ink colors (muted slate blue and warm ochre) printed on cream paper with slight ink texture and imperfect registration. Keep exactly the same framing, scale and position as the reference: head, neck and shoulders only, the head the same size and at the same height in the frame, facing the viewer straight on (frontal, symmetrical), neutral closed mouth, eyes open looking straight at the viewer, shoulders level, hands out of frame. Plain flat cream background with nothing else: no flowers, no clouds, no motifs, no text.