Add figma transformer package scaffold

[chubes4]

Summary

• Add a WordPress-native figma-transformer package alongside php-transformer.
• Establish the pipeline boundary for .fig/scenegraph input to normalized PHP IR to static HTML/CSS/assets.
• Add real fig-kiwi schema/message decoding, required zstd support, archive/image intake, normalized scenegraph rendering, external parity report contracts, docs, CLI, plugin helpers, and contract coverage.

Current scope

• .fig archive intake supports direct archives and wrapper ZIPs, embedded image metadata, zlib schema chunks, zstd message chunks, binary payload metadata, and decoded Kiwi Message payloads.
• The parser decodes embedded Kiwi schemas and NODE_CHANGES messages into scenegraph payloads consumable by the renderer.
• ext-zstd is now a Composer requirement for normal direct .fig imports. The library still exposes explicit callable/filter adapters, and the CLI supports --zstd-command=/path/to/zstd for local operator checks.
• Scenegraph rendering normalizes boxes, auto-layout, fill/hug/fixed sizing, constraints, clipping, transforms, text metadata, paints, strokes, image references, supported vector SVG paths, unsupported vector placeholders, components/instances, source reports, and diagnostics.
• Emitters stay source-derived: no hardcoded font/theme defaults; CSS is generated from Figma/IR fields plus a minimal reset.
• Parity reporting accepts external artifact metadata for source/generated screenshots, diff artifacts, viewport/frame metadata, mismatch metrics, and pass/fail/not-run states.
• Docs include a local fixture workflow that keeps real .fig files and generated evidence out of git.

Real fixture proof

• Operator-only fixture used locally: /Users/chubes/Downloads/Fisiostetic.fig (not committed).
• CLI proof with --zstd-command=/opt/homebrew/bin/zstd: success_with_warnings, 272 nodes, 24 output files, first file index.html.
• Decoded chunks: schema chunk zlib with 605 definitions, message chunk zstd decoded to NODE_CHANGES.

Remaining gaps

• Hosts need ext-zstd for normal direct .fig imports. If WPCOM/WP Cloud does not provide it, this package should not be enabled there until support is available or an approved adapter is registered.
• Visual parity scoring still needs a browser-backed external runner to attach screenshots/diffs.
• Some advanced Figma features still emit diagnostics/placeholders: unsupported effects, unresolved component references, and vector data without supported path geometry.

Verification

• php figma-transformer/tests/contract/run.php
• composer validate --working-dir=figma-transformer --strict
• git diff --check
• php figma-transformer/bin/figma-transformer /Users/chubes/Downloads/Fisiostetic.fig --zstd-command=/opt/homebrew/bin/zstd summarized locally; fixture/artifacts not committed.

AI assistance

• AI assistance: Yes
• Tool(s): openai/gpt-5.5 via OpenCode
• Used for: Drafting and integrating the PHP package foundation, fig-kiwi decoder, zstd requirement/adapter support, normalized scenegraph IR, static artifact emitter, rendering foundations, parity contract, docs, and contract tests.