figma-transformer: preserve clone-local geometry on frame rebase

[chubes4]

Summary

• Preserve component-source clone-local geometry when rebasing an explicitly selected frame to page origin.
• Keep transform/override-derived clone geometry eligible for normal page-origin localization.
• Add synthetic contract coverage for a selected frame containing a resolved component instance from a different canvas origin.

Verification

• composer test:contract
• php -d memory_limit=1G figma-transformer/bin/figma-transformer /Users/chubes/Developer/blocks-engine/figma-transformer/fixtures/🛠️ FSE Pilot Build Theme.fig --zstd-command=/opt/homebrew/bin/zstd --frame-id=3468:1038 --output-dir=/var/folders/lr/c_cmmt7s0592m4njz99v5yb40000gn/T/opencode/fse-pilot-compare/fix-transform

AI assistance

• AI assistance: Yes
• Tool(s): openai/gpt-5.5 via OpenCode
• Used for: Investigating the FSE Pilot fixture mismatch, implementing the normalizer fix, adding contract coverage, and running verification.