v2.0.0

What's Changed

• feat: add hashOperatorToken helper by @vvillait88 in #23
• feat: add usdToAtomic helper by @vvillait88 in #24
• feat: add detectRailFromHeaders helper by @vvillait88 in #25
• feat: re-export extractPaymentSignerFromAuth from payment subpath by @vvillait88 in #26
• feat: add zeroAmountCarveOut helper by @vvillait88 in #27
• feat: add classifyOrchestrationError helper by @vvillait88 in #28
• feat: add loadUCPSigningKeyFromEnv helper by @vvillait88 in #29
• fix: export loadUCPSigningKeyFromEnv from top-level barrel + lock public surface by @vvillait88 in #30
• docs: list TEC-302 helpers in the README inventory by @vvillait88 in #31
• chore: wire knip as a dev tool for ongoing dead-code visibility by @vvillait88 in #32
• refactor(challenge): flatten 8 challenge builders to destructured kwargs by @vvillait88 in #33
• refactor(payment): flatten x402 verify/settle/validate to kwargs by @vvillait88 in #34
• refactor(payment): flatten directive + headers + idempotency + zero-settle to kwargs by @vvillait88 in #35
• refactor(payment): flatten paymentRequiredHeader to kwargs; drop respond402 bridge by @vvillait88 in #36
• refactor(stripe-multichain, mppx): flatten 5 helpers to kwargs by @vvillait88 in #37
• refactor(discovery): flatten 6 discovery builders to kwargs by @vvillait88 in #38
• refactor(identity ucp + denial): flatten 5 wrappers to kwargs by @vvillait88 in #39
• refactor(identity): flatten loadUCPSigningKeyFromEnv to destructured kwargs by @vvillait88 in #40
• refactor(node): flatten remaining *Options + *Input wrappers — completes node-side TEC-303 train by @vvillait88 in #41
• feat(payment): add canonical *RailSpec types for cross-helper rail config by @vvillait88 in #43
• docs(example): drop stale AgentScoreGateOptions reference by @vvillait88 in #42
• refactor(challenge): buildAcceptedMethods consumes *RailSpec; async by @vvillait88 in #44
• refactor(identity/ucp): payment handlers consume *RailSpec by @vvillait88 in #45
• feat(payment)!: createMppxServer consumes Record<string, *RailSpec> by @vvillait88 in #46
• feat(challenge)!: respond402 returns framework-neutral Respond402Result by @vvillait88 in #47
• feat(checkout): add Checkout orchestrator (cross-language parity with python) by @vvillait88 in #48
• feat(checkout): seamless merchant helpers + Tier 1+2+3 SDK lifts by @vvillait88 in #49
• docs(examples): migrate 6 examples to Checkout + canonical 2.0 surface by @vvillait88 in #50
• feat: commerce 2.0.0 — Checkout orchestrator + per-framework adapters + signed UCP routes by @vvillait88 in #51

Full Changelog: v1.8.1...v2.0.0