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/num-traits-c8e95bd9b788a683/build-script-build-script-build.json

@@ -0,0 +1 @@
+{"rustc":11835527281324007204,"features":"[\"i128\"]","declared_features":"[\"default\", \"i128\", \"libm\", \"std\"]","target":5408242616063297496,"profile":11528375766455597691,"path":10116947317515136004,"deps":[[1924499573722464170,"autocfg",false,11790635573419656582]],"local":[{"CheckDepInfo":{"dep_info":"debug/.fingerprint/num-traits-c8e95bd9b788a683/dep-build-script-build-script-build","checksum":false}}],"rustflags":[],"config":9396254390672932401,"compile_kind":0}