Always-on LoopWatchdog (armed in TUI.start/stop) logs ui.loop-blocked with blockedMs and the current loop phase on the rising edge of a late probe tick. New pushLoopPhase/popLoopPhase/currentLoopPhase stack in pi-utils feeds it; breadcrumbs at in-process subagent dispatch (subagent:<id>) and the SelectList fuzzy filter (ui.select-filter) attribute residual main-thread stalls.
metaphorics