Stop excluding src/payments/types.ts from coverage; add test:component to CI

[Jesssullivan]

Two follow-ups deferred from PR #99 review because the owning files conflict with open PRs:

1. vitest.config.ts (owned by open PR chore: land devshell, docs, and toolchain truth normalization (TIN-89) #96) excludes src/payments/types.ts from coverage with the comment 'Types only'. That was already stale (createPaymentRegistry lives there) and is more so after fix(payments): normalize public card payment method boundary #99: the file now hosts the public payment-method id normalization runtime (toPublicPaymentMethodId/toInternalPaymentMethodId/isCardPaymentMethodId/isManualPaymentMethodId, toPublicPaymentMethodOption, registry resolution + dedupe). None of it counts toward the 70% threshold gate. Remove the exclude after chore: land devshell, docs, and toolchain truth normalization (TIN-89) #96 lands.

2. .github/workflows/ci.yml runs lint/typecheck/test:unit/test:integration/build/bazel but not pnpm test:component (vitest.component.config.ts, tests/e2e/**). The render-level checkout tests added in fix(payments): normalize public card payment method boundary #99 (tests/e2e/hybrid-checkout-drawer.test.ts, tests/e2e/payment-selector.test.ts) are therefore validated only locally. Add the component lane to CI.

Sequencing: wait for #96 to land, then a small PR can do both.