v0.19.2 — CI compatibility fix

Compatibility patch for the public alpha. Use this release instead of v0.19.1 for cross-platform source validation.

• Fix a test that assumed every Python build rejects deeply nested JSON at the same decoder depth. Both decoder rejection and schema rejection remain valid fail-closed outcomes.
• Add a deterministic check that decoder recursion errors return a machine-readable CLI error, exit code 2, and false input-contract/training-readiness flags.
• Rebuild the source ZIP, English materials bundle, sdist, and wheel as version 0.19.2. Refresh the changelog and published validation record.

Validation: the local Python 3.12 suite ran 712 tests successfully with 11 optional checks skipped. The extracted-source suite, 443-file public manifest, materials audit, distribution checks, installed-wheel checks, fixture validation, and offline demo passed. GitHub CI checks Python 3.10 and 3.12.

All six attached assets include the corrected source or its checksums. Runtime input validation is unchanged. This remains an infrastructure research prototype with English documentation and an MIT license; it does not introduce forecasting model results, GPU training, or a hosted leaderboard.