egutierrez
e828af3ac1
feat(shaders_lab): Output node + Functions palette with drag-drop
- DagKind::Output (new enum): terminal sink; compiler wires fragColor to its source_ids[0]
- dag_catalog: "output" node (1 input, red)
- dag_compile: skips Output in node_<i> emission; final fragColor resolves from Output's connection
- dag_node_editor: no more Add button; drops "DAG_NODE_TYPE" payloads at mouse canvas position; Output cannot be deleted; Output has no output pin
- dag_palette (new fn): Functions window with grouped, draggable node cards
- main.cpp: "Functions" window added; ensure_dag_default seeds plasma + connected Output