fix(frontend): move usage limits to left column on billing page

Move CoPilot Usage Limits below Automatic Refill Settings in the left
column and add "Open CoPilot" button for consistency with other sections.

autogpt_platform/frontend/src/app/(platform)/profile/(user)/credits/page.tsx

@@ -30,11 +30,17 @@ function CoPilotUsageSection() {
   if (usage.daily.limit <= 0 && usage.weekly.limit <= 0) return null;
 
   return (
-    <div className="space-y-4">
+    <div className="my-6 space-y-4">
       <h3 className="text-lg font-medium">CoPilot Usage Limits</h3>
       <div className="rounded-lg border border-neutral-200 p-4 dark:border-neutral-700">
         <UsagePanelContent usage={usage} showBillingLink={false} />
       </div>
+      <Button
+        className="w-full"
+        onClick={() => (window.location.href = "/copilot")}
+      >
+        Open CoPilot
+      </Button>
     </div>
   );
 }
@@ -255,12 +261,12 @@ export default function CreditsPage() {
               </Button>
             )}
           </form>
+
+          {/* CoPilot Usage Limits */}
+          <CoPilotUsageSection />
         </div>
 
         <div className="my-6 space-y-4">
-          {/* CoPilot Usage Limits */}
-          <CoPilotUsageSection />
-
           {/* Payment Portal */}
           <h3 className="text-lg font-medium">Manage Your Payment Methods</h3>
           <p className="text-neutral-600">