Preserve Figma fidelity across responsive component transforms

[chubes4]

Summary

• preserve semantic image elements without repainting the same source as a CSS background
• keep inferred foreground callouts above image-only media and bound desktop-only responsive fallbacks
• retain responsive stylesheet-owned heights instead of promoting them into forced inline geometry
• preserve mixed-content component layout while keeping vector-only instance scaling intact
• carry nested SVG and native button geometry through WordPress block lowering

Verification

• composer test:contract in figma-transformer
• composer test in php-transformer
• real Fisiostetic .fig transform at source, desktop, and mobile widths
• canonical wordpress-site-plan/v2 compilation with zero fallbacks and a passing quality gate
• WordPress 7.1 desktop/mobile rendering through the Studio acceptance path

The final WordPress render preserves one hero image, image/callout stacking at z-index 1/2, and the footer control at 72.891px high with a 36.438px icon and 51.428px authored corner radius at both 1440px and 390px widths.

Closes #1072
Closes #1073
Closes #1074
Closes #1075
Closes #1085

AI assistance

OpenAI GPT-5.6 Sol via OpenCode helped trace the Figma scenegraph, emitter, responsive CSS, SVG materialization, and native button projection paths; build regression contracts; and run the static and WordPress acceptance checks. Chris Huber reviewed and remains responsible for every line.