feat(FN-3911): reserve chat session text space for delete button

Fixes a layout issue where chat session rows did not reserve space for the delete button, which could cause text to be obscured when the button appeared. Added a CSS rule to maintain consistent spacing and a test to assert the reservation behavior.

Fusion-Task-Id: FN-3911

packages/dashboard/app/components/ChatView.css

@@ -248,6 +248,7 @@
   white-space: nowrap;
   overflow: hidden;
   text-overflow: ellipsis;
+  padding-right: calc(var(--space-md) * 3);
 }
 
 .chat-session-preview {
@@ -256,6 +257,7 @@
   white-space: nowrap;
   overflow: hidden;
   text-overflow: ellipsis;
+  padding-right: calc(var(--space-md) * 3);
 }
 
 .chat-session-meta {
@@ -1348,6 +1350,11 @@
     min-height: calc(var(--space-lg) * 2.25);
   }
 
+  .chat-session-title,
+  .chat-session-preview {
+    padding-right: calc((var(--space-lg) * 2.25) + var(--space-sm));
+  }
+
   .chat-message--assistant .chat-message-render-toggle {
     opacity: 1;
   }