fix(chat): set consistent 720px content width for chat and input bar (onyx-dot-app#10032)

Author: nmgarza5

web/src/app/app/message/MultiModelResponseView.tsx

@@ -30,7 +30,7 @@ const SELECTION_PANEL_W = 400;
 // Compact width for hidden panels in the carousel track
 const HIDDEN_PANEL_W = 220;
 // Generation-mode panel widths (from Figma)
-const GEN_PANEL_W_2 = 640; // 2 panels side-by-side
+const GEN_PANEL_W_2 = 720; // 2 panels side-by-side
 const GEN_PANEL_W_3 = 436; // 3 panels side-by-side
 // Gap between panels — matches CSS gap-6 (24px)
 const PANEL_GAP = 24;

web/src/app/css/sizes.css

@@ -1,5 +1,5 @@
 :root {
-  --app-page-main-content-width: 52.5rem;
+  --app-page-main-content-width: 45rem;
   --block-width-form-input-min: 10rem;
 
   --container-sm: 42rem;