Validation evidence: Make Fix node (recreate) work inside a subgraph

Implementation: cb82b1c86262a5691533606decb7c0bd2e04d738 on fix/v3-node-fixer-subgraph, targeting main.

v3-node-fixer-subgraph-pr-assets/annotated/: the captures with boxes and captions laid over them
v3-node-fixer-subgraph-pr-assets/screens/: the unmodified browser captures
v3-node-fixer-subgraph-pr-assets/evidence.json: what was captured, from which node_fixer.js, with hashes
v3-node-fixer-subgraph-pr-assets/capture_evidence.cjs: the script that made the captures
manifest.json: checksums of the files here