Fix dropdown text being cut off at the bottom

Added CSS to ensure proper height and padding:
- min-height: 48px (provides enough vertical space)
- line-height: 1.5 (proper text spacing)
- padding: 0.75rem (matches Bootstrap form-control-lg)

This prevents the selected recipient name from being cut off
at the bottom of the dropdown field.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/views/messages/index.html.erb

@@ -307,6 +307,13 @@ $("#submit_button").click(function(event) {
     }
   }
 
+  /* Fix dropdown height and padding to prevent text cutoff */
+  #message_receiver_id {
+    min-height: 48px;
+    line-height: 1.5;
+    padding: 0.75rem 0.75rem;
+  }
+
   /* Ensure dropdown has proper focus styling */
   #message_receiver_id:focus {
     border-color: var(--rg-success);