Exercise make demo-claude against the live Anthropic API

[Silousr]

make demo-claude is covered in CI only through its graceful no-key fallback, so the live agent loop has never actually run.

Worth verifying with a real ANTHROPIC_API_KEY:

• the tool loop completes and converges,
• Claude supplies the confirmation value for the S2 dispense command (safety gating works through an agent, not just a script),
• the signed bundle verifies afterwards.

Until then, treat the live path as unproven.