- Tracked placeholder/partial-result paints via render() override so an update landing before the shape reaches the terminal skips resetDisplay().\n- Added negative-case unit tests proving no reset fires when the intermediate shape was never painted.\n\nFixes #4314
- Added virtual-terminal coverage for SSH placeholder and partial-result repaint seams.\n- Asserted stale placeholder and pending rows disappear from the terminal buffer while current SSH output remains.\n\nFixes #4314
- Added renderer hooks for first-result placeholder replacement and partial-result settle repaints.\n- Enabled the hooks for SSH and covered the streamed-placeholder and settle seams.\n\nFixes #4314