Add detailed check inspection and prepare Ruby 0.0.2

[LukasNiessen]

Debug checks now show project roots, discovered files, dependencies/import kinds, selected files, projected dependencies, and passing metric values. Inspection is fiber-scoped and restores nested contexts on errors; options keep their identity and custom metric calculations still run once. The README documents all levels, CI log artifacts, and existing colored reports. Prepare compatible gem release 0.0.2.

Validation: 459 RSpec examples pass (one Windows symlink capability skip), with 99.0% line and 90.85% branch coverage; focused tests cover cold/cached graph inspection, nested/fiber/thread isolation, and single evaluation of passing custom metrics. Full compatibility, lint, documentation, package, and downstream fixture checks must pass before merge/release.

[TristanKruse]

Reviewed the fiber-scoped inspection context, restoration after nested checks/errors, cached graph inspection, and single-evaluation metric wrapper. All 459 local tests and coverage checks pass. Documentation rendering follow-ups and the unreleased heading cleanup are prepared for PR #51. This approval is for the existing Lukas-authored head 7ae18d8.