ZTARE v1.2.1 — Provider-free first-run hotfix

ZTARE v1.2.1 is a packaging hotfix for the v1.2 release.

Fixed

• Defers Google, Anthropic, and OpenAI SDK imports until a provider-backed benchmark path is selected.
• Restores the provider-free make first-run path on a clean base installation.
• Adds a standard-library-only regression test for offline ordinary-review prompt export.

The v1.2.0 Workbench, LeanMill/AxiomPack, and ARC-AGI WIP scope is unchanged.

Verification

• make first-run PYTHON=./venv/bin/python
• make gates
• make docs-check
• 17 constraint-memory ordinary-review tests