Adopt upstream clitest binary from Core

[jviotti]

No description provided.

[augmentcode]

🤖 Augment PR Summary

Summary: This PR replaces the repository-local Python CLI test interpreter with Core's upstream clitest binary.

Changes:

• Updates the vendored Core revision and enables its test and stacktrace language components.
• Registers JSON Schema CTest scripts directly against sourcemeta_core_clitest.
• Removes the Python interpreter dependency, its source file, and Python from the Alpine test image.
• Adds Core's C++ CLI-test runner, TAP reporting, DSL parser, checks, process execution, and filesystem commands.
• Adds Core Unicode validation, text replacement/join helpers, and binary-safe file reads used by the runner.
• Removes direct Snap workflow invocations of the deleted Python runner.

Technical Notes: The new runner provides isolated temporary sandboxes, explicit environment handling, deterministic stream observations, and static checks for vacuous scripts.

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[cubic-dev-ai]

All reported issues were addressed across 16 files

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