feat(checker): examples() and spec_files() carry the specification's files

A consumer of the checker crate needs no path into this repository.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp

target/debug/.fingerprint/syn-4a09dfaf801b5fae/invoked.timestamp

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+This file has an mtime of when this was started.

target/debug/.fingerprint/syn-4a09dfaf801b5fae/lib-syn

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+eff6a365dc54e30d

target/debug/.fingerprint/syn-4a09dfaf801b5fae/lib-syn.json

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+{"rustc":11835527281324007204,"features":"[\"clone-impls\", \"derive\", \"parsing\", \"printing\", \"proc-macro\"]","declared_features":"[\"clone-impls\", \"default\", \"derive\", \"extra-traits\", \"fold\", \"full\", \"parsing\", \"printing\", \"proc-macro\", \"test\", \"visit\", \"visit-mut\"]","target":9442126953582868550,"profile":11528375766455597691,"path":9491405516558862323,"deps":[[8949245912927223590,"quote",false,6148210718780026669],[16346726298725429545,"proc_macro2",false,12044787672170069212],[17795627090660149937,"unicode_ident",false,7464612875814476202]],"local":[{"CheckDepInfo":{"dep_info":"debug/.fingerprint/syn-4a09dfaf801b5fae/dep-lib-syn","checksum":false}}],"rustflags":[],"config":9396254390672932401,"compile_kind":0}