kibuilder: visual step-by-step assembly guides from KiCAD PCBs

A tool that turns any KiCAD PCB into a visual, stage-by-stage assembly guide. Each step pairs a high-quality OpenCASCADE render of the components added at that stage with a cumulative kicad-cli render of the board, composited into instruction-manual-style pages with step badges and quantity tags. Outputs per-stage images, a combined landscape PDF, and a GitHub-viewable Markdown guide. Includes a PyQt6 GUI for stage editing, component orientation, and height-based auto-staging.