Desktop: Improve Big Session Navigation - Scrollable (#6837)

packages/ui/src/components/message-nav.css

@@ -102,6 +102,8 @@
   align-items: center;
   border-radius: var(--radius-md);
   background: var(--surface-raised-stronger-non-alpha);
+  max-height: calc(100vh - 6rem);
+  overflow-y: auto;
 
   /* border/shadow-xs/base */
   box-shadow:

packages/ui/src/components/session-message-rail.css

@@ -7,6 +7,9 @@
   position: absolute;
   left: 1.5rem;
   margin-top: 0.625rem;
+  top: 0;
+  bottom: 8rem;
+  overflow-y: auto;
 }
 
 [data-slot="session-message-rail-compact"] {