- Output targets and sync clocks get start/stop (▶/■) with optimistic UI update
- Test/preview button for templates, sources, and KC targets
- Notification test button (🔔) for notification color strip sources
- Fetch batch states to show correct running status for output targets
- Sync clocks show running state from API (is_running)
- Surgical DOM patching (patchNodeRunning) preserves hover state on toggle
- Success button hover style (green) for start action
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>