[P1][Sprint 1][Growth] Add typed LTL and parcel fuel-surcharge clients #79

Why

The published API exposes six LTL/parcel fuel-surcharge routes, but no first-class Node resource.

Acceptance criteria

• Cover list, latest, and history routes for LTL and parcel carriers.
• Add TypeScript types for carrier, service level, mode, dates, pagination, and responses.
• Preserve effective dates and source provenance.
• Test unknown carrier, no-data, entitlement, malformed 200, 429, abort, and timeout paths.
• Add examples, docs, live smoke, capability metadata, and release.

Delivery

Independent npm release.