Hook for the outer optimizer: promote the most recent trial point into the
accepted series after the optimizer’s trust-region/line-search accepts it.
Paired with record_outer_eval in the bridges. Safe to call from any
thread; no-op when no visualizer is active or when no trial has been
recorded yet.
Hook for the outer optimizer: record a single objective+gradient evaluation
as a trial point. Threads through Arc<Mutex<...>> so deep solver call
stacks can publish samples without holding the session. No-op when no
visualizer is active (e.g. unit tests, embedded use). The renderer is
throttled internally (~40 ms interactive, ~1 s dumb) so spamming this from
a tight loop is safe.