Perch v1.35.1

v1.35.1 — stop the phantom "working" spinner on idle panes

Panes whose turn ended without a Stop hook (Esc interrupt, notification-
resumed turns) oscillated working↔done forever on ambient TUI repaints —
a configured statusline ticks every few seconds, and the idle watchdog
read each tick as the agent resuming. Resuming now requires sustained
output (byte growth across two consecutive watchdog ticks), so the
spinner settles and stays settled.