probe_window drained a source's entire close column just to learn its
first and last bar timestamp; both live callers (open_real_source and
campaign_window_ms on the campaign trunk) now resolve through
aura-ingest's new archive_extent(): list the symbol's SYM_YYYY_MM.m1
files, load only the boundary months via the existing loader seam, and
walk across gap months forward/backward — O(2 file loads) typical
instead of O(archive). Empty-window refusal semantics are unchanged
(pinned). Two characterization tests captured the resolved windows
against the OLD implementation over the synthetic per-test archive and
stay green unchanged after the swap.
Measured: the probe itself drops 366ms -> 13ms (~28x) on the full
2014-2026 GER40 archive; end-to-end command wall-clock moves only
~2-3% because the sim loop dominates — the fix removes an
O(archive-size) term, not the dominant cost.
closes#252
claude
a895891ab1