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

[karlwaldman]

Why

The published API exposes six LTL/parcel fuel-surcharge routes, but no first-class Python resource. This is a customer workflow already shipped by the API.

Acceptance criteria

• Cover list, latest, and history routes for LTL and parcel carriers.
• Type carrier, service level, mode, date, pagination, and response models.
• Preserve effective dates and source provenance.
• Test unknown carrier, no-data, entitlement, malformed 200, 429, and timeout paths.
• Add examples, docs, live smoke, capabilities metadata, and a minor release.

Delivery

Independent Python release.