Fix dashboard scrolling and lock generation contracts

[senlindesign]

Summary

• restore vertical Dashboard scrolling at common laptop viewport sizes while keeping fixed-size export routes isolated
• check in the editable React/CSS frontend source and add a deterministic rebuild path for hashed offline assets
• anchor generated illustrations to the versioned cw-pixel-diorama-v1 reference-conditioned visual contract
• tighten Coding Overview copy to two sentences using two or three representative facts
• update the Skill, bilingual README, changelog, contributor guide, release checklist, evaluator, and dashboard screenshot

Root cause and fix

The bundled CSS applied body { overflow: hidden } globally inside a desktop media query. The source now keeps ordinary pages on overflow-y: auto and scopes fixed overflow to html.export-page, body.export-page. Export pages additionally use a fixed viewport body so Page Down cannot shift the card.

Validation

• make frontend
• make validate — 14/14 checks passed
• make package
• archive integrity check passed for dist/coding-wrapped.skill
• browser regression checks passed at 1280 × 720, 1440 × 900, and 1024 × 768
• export route remained fixed under Page Down
• no unexpected horizontal scrollbar at the tested Dashboard sizes

Notes

Python remains the only runtime dependency for Skill users. Node.js is needed only by contributors rebuilding the checked-in Dashboard frontend.