Restructure runner turn settlement: replace TurnTransitionError defect
control flow with tagged turn results and a plain restart loop, name the
settlement evidence, and merge duplicated interrupt branches.
Split settled tool-fiber failures: tool implementation defects keep
surfacing as model-visible tool errors and the turn continues, while
typed ToolOutputStore errors now fail the assistant and the drain
instead of being silently absorbed.
Kit Langton
0d1ef5adb6