The frame echoes most panel content elsewhere - the session token appears in
recent events, a replying target names a chart series, and the sample
panel's last-warning row satisfies a loose warning search - so whole-frame
assertions kept claiming coverage they did not have.
Panels are now addressed structurally: has_panel matches a title in a top
border, panel_rows slices a panel's interior to its own columns, and
assertions run against the owning panel. That fixes the session token,
recent-events warning line, graph-view panel exclusions and graph-view
target rows, and converts the remaining whole-frame checks in the module so
the class of defect does not come back.
Each tightened assertion was confirmed to fail against a deliberate
regression of the behavior it protects.