fix(dashboard): chat-view fills full width of parent container

Same pattern as agents-view fix — .chat-view had display:flex + height:100%
but no flex or width, so it shrank to content width (~270px) instead of
filling the .project-content parent.

packages/dashboard/app/components/ChatView.css

@@ -2,6 +2,8 @@
 
 .chat-view {
   display: flex;
+  flex: 1;
+  width: 100%;
   height: 100%;
   overflow: hidden;
 }