feat: enhance platform dashboard UX and add security controls

- Move Add Company button to Companies card header for better context
- Add smart Save Changes button that only appears when data is modified
- Implement navigation protection with unsaved changes warnings
- Add company status checks to prevent suspended companies from processing data
- Fix platform dashboard showing incorrect user counts
- Add dark mode toggle to platform interface
- Add copy-to-clipboard for generated credentials
- Fix cookie conflicts between regular and platform auth
- Add invitedBy and invitedAt tracking fields to User model
- Improve overall platform management workflow and security

app/platform/login/page.tsx

@@ -8,6 +8,7 @@ import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { Alert, AlertDescription } from "@/components/ui/alert";
+import { ThemeToggle } from "@/components/ui/theme-toggle";
 
 export default function PlatformLoginPage() {
   const [email, setEmail] = useState("");
@@ -43,7 +44,10 @@ export default function PlatformLoginPage() {
   };
 
   return (
-    <div className="min-h-screen flex items-center justify-center bg-gray-50 dark:bg-gray-900">
+    <div className="min-h-screen flex items-center justify-center bg-gray-50 dark:bg-gray-900 relative">
+      <div className="absolute top-4 right-4">
+        <ThemeToggle />
+      </div>
       <Card className="w-full max-w-md">
         <CardHeader className="text-center">
           <CardTitle className="text-2xl font-bold">Platform Login</CardTitle>