ToolExecutionComponent.#updateDisplay() re-ran renderResult (O(result-size)) on every invalidate - spinner ticks, stream chunks, resizes, keystrokes - so large results blocked the loop for seconds and typing lagged. It now early-returns on an unchanged dirty key (result version, expanded, partial, spinner frame, image visibility, theme epoch), and theme.ts exposes getThemeEpoch() bumped on every theme swap so cached blocks re-render on theme change.
can1357