feat(platonic-folding): add source-backed adapter

[alowpoly]

Summary

• add a source-pinned XScreenSaver Platonic Folding adapter with dedicated desktop and mobile prepared playback banks
• prepare the five source solids, fold motion, two-sided lighting, and specular response into 64 raster states per face
• mount one shared static-prepared PolyCSS Morph graph with 50 stable face roots/leaves and at most 20 visible
• add deterministic preparation, provenance/license records, a headless CGL native oracle, browser capture, tests, performance tooling, and deploy-preview wiring

Runtime contract

• retained DOM topology; no runtime geometry construction, atlas rasterization, or DOM growth
• direct source-ordered publication through createPolyMorphPreparedDomTarget
• no full prepared-state materialization, full-state diff, matrix formatting, id lookup, or normal-path full graph scan
• no requestAnimationFrame loop; one source-cadence timer consumes sparse preformatted operations
• loop wrap is separately prebaked and performs no hidden shape or atlas writes
• selected prepared-bank payload is 1.59 MB raw, about 0.96 MiB gzip or 0.90 MiB Brotli; the raster atlas decodes to 51.6 MiB
• release preparation fetches the two pinned source files and verifies both locked SHA-256 identities before building

Visual qualification

This is a source-faithful bounded approximation, not a pixel-identical claim.

• native A/A and browser A/A captures are exact
• 37-pose oracle across all five solids: worst mean absolute channel delta 0.568905
• worst changed-pixel ratio above the 8-channel tolerance: 0.011851
• separate 26-angle closed-tetrahedron sweep: worst mean absolute channel delta 0.200158
• sparse playback reconstructs all 2,710 source frames and the loop boundary with canonical PolyCSS matrix formatting

Performance evidence

Fresh isolated desktop and mobile Chrome traces show:

• desktop timer work fell from 0.2066 ms to 0.1218 ms per callback, a 41% reduction
• mobile timer work fell from 0.1999 ms to 0.1130 ms per callback, a 43% reduction
• zero layout in both traces
• stable 50-root / 50-leaf DOM with zero child-list mutations
• browser counters confirm zero prepared-state materializations, full-state diffs, runtime matrix formats, runtime id lookups, normal-path full scans, and hidden wrap writes

Validation

• pnpm test:platonic-folding
• pnpm prepare:platonic-folding:check
• pnpm build:platonic-folding
• pnpm test:platonic-folding:browser
• pnpm oracle:platonic-folding
• pnpm verify:source-only
• pnpm typecheck
• desktop and mobile smoke passed on https://deploy-preview-91--cssgraphics.netlify.app/platonic-folding/

[netlify]

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