Cap floating IPs table width to max-w-lg on instance create form (#3079)

The floating IPs MiniTable container was unconstrained, causing it to
stretch wider than other fields. Add max-w-lg to match the empty state
and other sections in the form.

Closes #3078 

https://claude.ai/code/session_01JAbgycxitZnU3ii4FzFuNd

Co-authored-by: Claude <noreply@anthropic.com>

Author: david-crespo

app/forms/instance-create.tsx

@@ -1001,7 +1001,7 @@ const NetworkingSection = ({
             />
           </div>
         ) : (
-          <div className="flex flex-col items-start gap-3">
+          <div className="flex max-w-lg flex-col items-start gap-3">
             <MiniTable
               ariaLabel="Floating IPs"
               items={attachedFloatingIpsData}