v0.3.0

Changed (wire shape)

• AP2 routing context (host, currency, payment_protocol) moved from Action.policy_keys to Subject.dimensions["payee_website" / "payment_currency" / "payment_protocol"]. The v0.1/0.2 placement on Action.policy_keys was per the cycles-action-kinds-v0.1.26.yaml extension; production cycles-server v0.1.25.x doesn't yet implement that extension and rejected the field with 400 Malformed request body. v0.3 ships these values on Subject.dimensions (part of the base protocol), so the wrapper works against current production servers. The client-side RuntimeAuthorityReceipt.policy_keys still carries the canonical shape — dashboards / dispute evidence / audit pipelines that consumed the receipt are unchanged.

Unchanged

• Public Python API (cycles_guard_payment, cycles_guard_payment_async, all exception classes, all class attributes, AP2Mandate, RuntimeAuthorityReceipt).
• Exception contract.
• Idempotency-key derivation (still ap2:open_mandate:{...} or ap2:tx:{...}).
• All v0.2.0 features (async, commit-uncertainty handling, cancellation handling).

Still planned for v0.4+

• Multi-currency (still raises AP2CurrencyError on non-USD).
• payment.refund convenience helper.
• Opt-in flag to re-emit Action.policy_keys for servers that implement the v0.1.26 extension.
• Server-verifiable runtime-authority receipt (requires cycles-protocol signed-receipt field).