position ranks an issue inside its own (workspace, status) column, but a
status change carried the old column's value over unchanged. The value
that put an issue on top of Todo is roughly zero, and lands it below
every hand-dragged issue in Done — so agent-completed work sank into the
middle of a long Done column and read as "the task disappeared".
Re-rank to the top of the destination column on both status-write paths,
reusing the MIN(position) - 1 policy new issues already get. An explicit
position still wins, so cross-column drag-and-drop keeps the slot it
dropped on, and a same-status write leaves position alone.
The re-rank reads MIN(position) for the destination (workspace, status),
which idx_issue_status could only serve with a heap fetch per issue in
the column — paid on every completion against the column that grows
without bound. Add (workspace_id, status, position) to make it an
index-only min.
Closes#7410
Co-authored-by: J <[email protected]>
Co-authored-by: multica-agent <[email protected]>
