fix: follow per-agent sidebar rows for status words and clip them to the row

The daemon's [ui.sidebar.agents] rows may name the state_text token, which
the terminal client prints as a status word beside each agent. The native
client ignored the field and drew only the status dot, so the two clients
disagreed and a glance could not tell working from idle.

Read the daemon's sidebar rows (rows and rows_by_agent) alongside its other
settings and, when state_text is configured, paint the status word at the
trailing edge of every agent row in the dot's color, in every layout. Rows
without the token keep the dot alone, matching the daemon's default rows.

Add regression tests for the config reader and for the rendered word in all
four layouts.