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-4d0606b740c78087/lib-num_traits.json

@@ -0,0 +1 @@
+{"rustc":11835527281324007204,"features":"[\"i128\"]","declared_features":"[\"default\", \"i128\", \"libm\", \"std\"]","target":4278088450330190724,"profile":2579911162000070427,"path":8897503837210747895,"deps":[[5157631553186200874,"build_script_build",false,11772677931278839475]],"local":[{"CheckDepInfo":{"dep_info":"debug/.fingerprint/num-traits-4d0606b740c78087/dep-lib-num_traits","checksum":false}}],"rustflags":[],"config":9396254390672932401,"compile_kind":0}