v2.0.13

What's Changed

• fix(sdk): make unmetered budget spend explicit and finish the #421 contract by @kjgbot in #423
• fix(sdk,kernel): carry unmetered dollars across prior spend by @kjgbot in #425
• fix(drive): trust an escalation only when this tick wrote it by @kjgbot in #429
• fix(sdk): make a failed step diagnosable instead of a protocol_error by @kjgbot in #430

Full Changelog: v2.0.12...v2.0.13