automation: beside-target-place - #863

work#311: drop:beside resolves against the target place's own edge, not the active pane's; wide-source/tall-target regression fails under a source-global callback. Author linux/claude; windows/claude F1-F4 fixed, linux/claude and linux/codex clean (linux/codex at head 0538d8e, integration 94/94); full CI green on all three OSes. windows/codex F1 (index out of bounds at c656b43) came from a degraded run (local processes failing with 0xC0000142, an unmerged branch whose diff carried unrelated main commits); Tests (Windows) passes at this head, so it does not stand. Past round two: my one decision is merge.