A Frankfurt-baked zero-arg Session preset (open 09:00 Europe/Berlin as
literals) joins the std vocabulary as SessionFrankfurt, declaring
period_minutes: I64 (default 15) as its one scalar knob — the
single-knob roster pattern the cost nodes established. A data-only
blueprint can now reach a session/time-of-day stream (bars_since_open),
unblocking time-of-day conditioners for the confirm/refute research
model. Roster count pins bump 28 -> 29 in both conscious-act sites.
Fork decision on the issue: the preset variant over a param-vocabulary
extension — a timezone param would need a string kind, breaching the
four-scalar discipline; the preset keeps the vocabulary closed and is
the additive extension the roster-exclusion comment anticipates. The
4-arg Session::builder stays untouched; in_session/session_open_ts
stay deferred (#154).
closes#261
claude
ca4a89864c