feat(js): support new checkout totals shape #29012

Job	Run time
Check Permissions	5s
Build Packages	1m 13s
Formatting \| Dedupe \| Changeset	1m 4s
Unit Tests (**)	2m 27s
Static analysis	1m 18s
Unit Tests (**)	2m 11s
Publish with pkg-pr-new	1m 7s
Integration Tests (ap-flows, chrome)	1m 53s
Integration Tests (tanstack-react-start, chrome)	1m 43s
Integration Tests (generic, chrome)	5m 39s
Integration Tests (express, chrome)	1m 38s
Integration Tests (astro, chrome)	2m 38s
Integration Tests (vue, chrome)	1m 35s
Integration Tests (sessions, chrome)	2m 15s
Integration Tests (sessions:staging, chrome)	2m 20s
Integration Tests (custom, chrome)	2m 13s
Integration Tests (react-router, chrome)	1m 35s
Integration Tests (hono, chrome)	2m 23s
Integration Tests (handshake, chrome)	1m 18s
Integration Tests (handshake:staging, chrome)	1m 26s
Integration Tests (quickstart, chrome, 16)	2m 20s
Integration Tests (quickstart, chrome, 15)	2m 31s
Integration Tests (nuxt, chrome)	2m 5s
Integration Tests (fastify, chrome)	1m 44s
Integration Tests (billing, chrome)	5m 6s
Integration Tests (machine, chrome)	5m 13s
Integration Tests (nextjs, chrome, 15)	5m 39s
Integration Tests (localhost, chrome)	1m 46s
Integration Tests (chrome-extension, chrome)	1m 54s
Integration Tests (cache-components, chrome, 16)	2m 33s
Integration Tests (nextjs, chrome, 16)	5m 2s
	1h 13m 54s

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