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/include_dir-0e5737e22c7f7986/lib-include_dir.json

@@ -0,0 +1 @@
+{"rustc":11835527281324007204,"features":"[\"default\"]","declared_features":"[\"default\", \"glob\", \"metadata\", \"nightly\"]","target":10480666333777355507,"profile":8979240926782815398,"path":13368163027057289627,"deps":[[4014822085478067054,"include_dir_macros",false,4163319474151446795]],"local":[{"CheckDepInfo":{"dep_info":"debug/.fingerprint/include_dir-0e5737e22c7f7986/dep-lib-include_dir","checksum":false}}],"rustflags":[],"config":9396254390672932401,"compile_kind":0}