The maintainer's promised merge-time fixes from the final review of #453:
1. closeSplitPane() tears down a divider drag still in progress, so a split
that collapses mid-drag no longer leaves body.split-pane-resizing (the
page-wide col-resize cursor and user-select lock) set until a reload.
2. openSplitPane() re-applies the picker's own exclusions (detached session,
pid === null, no session record) for a row that went stale while the
menu sat open, refusing silently like its neighbouring gates.
3. architecture-invariants: the hard-hide of .btn-split is the
@media (max-width: 1179px) rule in styles.css, not mobile.css.
4. SplitTerminalPane.destroy() nulls onclose (and onerror) beside onopen
and onmessage.
5. Picker rows drop the data-session-id attribute nothing read.
6. The Pane-A-ends branch collapses with skipPrimaryResize, so the closing
resize is no longer aimed at the session the server just removed.
7. The {t:'r'} refresh path is single-flight across the fetch and the
chunked write, coalescing a mid-replay refresh into one trailing re-run.
Tests: split-pane-auto-collapse-unit gains the drag-teardown, exclusion and
skip-resize cases; the new split-pane-terminal-unit covers destroy() and the
refresh single-flight. All were run against the pre-fix module to confirm
they fail there.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
(cherry picked from commit dbd39aed015ae5ae5870aba398bf4b4ab5118e47)