Generate dynamic diagrams (via Excalidraw) (#940)

Add support for generating dynamic diagrams in flow with Excalidraw (https://github.com/excalidraw/excalidraw). This happens in three steps:
1. Default information collection & intent determination step.
2. Improving the overall guidance of the prompt for generating a JSON, Excalidraw-compatible declaration.
3. Generation of the diagram to output to the final UI.

Add support in the web UI.

src/interface/web/app/chat/chat.module.css

@@ -79,7 +79,7 @@ div.titleBar {
 div.chatBoxBody {
     display: grid;
     height: 100%;
-    width: 70%;
+    width: 95%;
     margin: auto;
 }