fix(provider-pi): fork before a running turn whose start entry was not captured yet

A running boundary turn has no completedAt, so the uncaptured session-tree
search rejected it and forking an earlier turn failed. Leave the search window
open-ended for a running turn; the lower bound and earliest-user-entry rule
are unchanged.

Fixes #23050

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
111dadc991Julius Marminge committed on 10/21/2026, 7:33:27 PMparentc208208
1 file changedLine totals unavailable