Third of the five remaining items on #23.
`add_events_with_prior` and `TimeSlice::add_events` took `Vec<Vec<f64>>` and
`Vec<Vec<Vec<f64>>>` where an empty vec meant "not supplied" — so an empty
outer vec and a genuinely empty event list were the same value, and every
reader had to know which. Both are now `Option`, and the "not supplied"
branches read as `None` arms rather than `is_empty()` checks.
Two things fell out of the change that a sentinel would have hidden:
The tie pre-check iterated `results` directly. Under `Option` it needs
`.iter().flatten()`, which makes explicit that a `None` results list has no
ties to reject — previously an empty vec silently skipped the same loop and
looked identical to "checked, found nothing".
`MismatchedShape.got` could no longer be `results.len()`, because at the point
of the error there may be no vec to take a length from. It is now computed as
`map_or(0, Vec::len)` before the error is built.
MSRV note: my first draft used let-chains for the two validations. Those need
Rust 1.88 and this crate pins 1.85 — it compiled locally on 1.98 and would
have failed only in the MSRV CI job. Rewritten with `is_some_and`, and
verified by installing 1.85.0 and building against it rather than by assuming
the removal was complete.
Breaking: `TimeSlice::add_events` is public.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T5SYDExxL4vZgvunrcNSMc
TimeSlice<T> gains a pub(crate) convergence: ConvergenceOptions field
set at construction. TimeSlice::new now takes it as a third parameter
(breaking change to the pub constructor, acceptable in 0.1.x).
History::add_events_with_prior passes self.convergence so the propagated
value reaches every TimeSlice. The pre-existing convergence-the-method
is renamed to iterate_to_convergence to disambiguate from the new
convergence-the-field.
The field is wired but not yet read by inference -- the three
Game::*_with_arena callsites in time_slice.rs still hardcode
ConvergenceOptions::default(). Task 2 changes that. Bit-equal because
the propagated value equals the hardcoded value end-to-end.
Also updated benches/batch.rs which has a fourth TimeSlice::new
callsite (not enumerated in the plan -- only src/ files were).