- Register VideoFrameGrabNode in node exports, nodeTypes map, and minimap colors
- Add to ConnectionDropMenu as video target (Frame Grab) and image source
- Add executeVideoFrameGrab executor with canvas-based frame extraction
- Wire into all three execution paths: executeWorkflow, regenerateNode, executeSelectedNodes
- Add video connection validation for videoFrameGrab target type
- Add handle mapping for video->videoFrameGrab and videoFrameGrab->image connections
- Add videoFrameGrab case to quickstart validation defaults