[Graph-UI] Parse DSL as Graph Nodes and Edges

[Helltab]

Parse DSL as Graph Nodes and Edges:
The DSL comes from the backend. The following tasks are involved in this process:

1. use valtio as the graph state
2. define branch node
3. define llm node
4. define start node
5. define end node
6. define knowledge retrieval node
7. define variable aggregator node
8. create toolbar top of the map
9. create toolbar bottom of the map
10. create toolbar float with the node
11. create contextMenu

[Helltab]

I'll have a try.