GeezerVison

Summary

Split the non-raw reporting changes out of #9628 for separate review and merge. This PR does not collect or compare native __text_signature__ values, save JSON result files, or upload CI artifacts. Existing inspect.signature comparison and --json stdout mode remain.

• Preserve reference inventory diagnostics, expanded/empty classes, class-selection decisions, and actual scan/import/parent observations.
• Report CPython introspection failures as uncomparable rather than treating exceptions as reference signatures. Keep builtin/module name collisions from affecting classification.
• Include failed reference imports and builtin signature inventory in the report, and reject a failed comparison subprocess.
• Keep the 28 non-raw focused tests in scripts/tests/test_whatsleft.py.

Only the reporting script and its tests differ from main. The CI workflow is byte-identical to main. No runtime, Lib, generated report, new CI test step or parity gate is included. Existing reference discovery is retained.

Split and merge order

Merge this PR separately first. #9628 remains a draft dependent follow-up containing raw text-signature observation/comparison and optional result-file/CI-artifact persistence. Its prerequisite is this exact head. Do not merge #9628 as an alternative to this PR; after this merges, refresh its branch against main so only the follow-up remains.

Validation

Head: 116d1106a62, based on main 42d26965cf8f.

• All 28 focused tests pass with CPython 3.15.0, also independently verified. The same tests previously passed reversed and three shuffled orders; removing persistence did not change them.
• A complete CPython-only self-scan succeeds. JSON stdout equals the previously verified non-raw report exactly; only optional persistence was removed.
• Independent review verifies the delta removes only --json-output, its file-write block, and CI sidecar/upload changes. All coverage, inventory and error-reporting behavior remains.
• The 62 original non-raw assertions are preserved. Raw-only tests/assertions remain in Guard raw and inspected signature observations in CI #9628, whose full tree is byte-identical to the original combined tree.
• Normal repository hooks and git diff --check pass.

These self-scans are not RustPython execution results. Local native RustPython, workspace/C API tests and Clippy were not run under the coordinated native-build reservation. Exact-head hosted CI is pending.

AI assistance

The split, tests and independent review were assisted by dot. The runtime does not expose an exact model version.