* decode bench + oracle + rewrite encode oracle

* docs iter

* Apply suggestions from code review

Co-authored-by: Simon Brandeis <33657802+SBrandeis@users.noreply.github.com>

* decode_batch + decode_stream surface

* decode oracle: specials, pairs, stream, batch + one test per model x fixture

* oracle sweeps add_special_tokens; benches encode with specials

* simplify oracles: fixed windows, per-model tests, no macros

* fix: doctest

* charts: honest decode-memory rows, decode basis + flags spelled out

* fix stubs?

* ci: pin ruff, 0.16 breaks legacy python style