fix: UST endpoints have no pagination/date-range params — align SDK to API

[alexpipipi]

Problem

The US Treasury (UST) endpoints (/api/ust/yield-rates, /bill-rates, /real-yield-rates, /long-term-rates) do not support pagination or date-range filtering. Verified against the live API (2026-07-28): page[limit], page[offset], from, and to are all silently ignored — the full dataset for the requested year is always returned. The only real query param is filter[year] (defaults to current year).

The Python SDK previously exposed from_date / to_date params on all four UST methods, misleading users into thinking date-range filtering worked.

Fix

• Removed from_date / to_date from the four TreasuryAPI methods and the internal helper, plus the apiclient facade wrappers.
• Updated docstrings; added a class-level note that these endpoints ignore pagination/date-range params.
• Replaced the test_date_params test (which asserted the ignored params were emitted) with test_no_pagination_or_date_params, asserting the SDK does not emit from / to / page[...].

No pagination params were present in the SDK. No new params invented — filter[year] was not previously exposed and is left as-is (out of scope for this doc-correction).

Tests

python3 -m pytest tests/ — 141 passed.

Ties to DEV-1934.