A run of adjacent calls is drawn as one collapsed card, which hid the one
thing worth seeing without opening anything: the command the session is
running right now. It is a row of its own while it runs and folds back into
the run when it ends.
Grouping stays a display decision, so the pieces a running call cuts a run
into are keyed there. The first piece keeps the run's name -- that name is
what survives a page of history landing in front of it -- and later pieces
take their own first call's id behind it, since the call a run was named
after can itself be the one running.
The echo rig's /tools gap now runs between a call's start and its end rather
than between one call and the next, which is where a real session's time goes
and what makes the running state observable at all.
Checked with ktfmtFormat, compileDebugKotlin, testDebugUnitTest (new
ToolRowsTest) and lintDebug, cargo fmt/clippy/test, and on the emulator
against the sandbox: "Called 2 tools" with the live Bash card beneath it.
