Refactor project and contract forms for improved UI and functionality

- Updated NewProjectPage to use PageContainer and PageHeader for better layout.
- Enhanced ProjectListPage to display project data in a responsive table format.
- Refactored ContractForm to use Card components and improved loading state handling.
- Refactored ProjectForm to use Card components, added loading state, and improved form structure and styling.

src/app/contracts/new/page.js

@@ -1,10 +1,39 @@
 import ContractForm from "@/components/ContractForm";
+import PageContainer from "@/components/ui/PageContainer";
+import PageHeader from "@/components/ui/PageHeader";
+import Button from "@/components/ui/Button";
+import Link from "next/link";
 
 export default function NewContractPage() {
 	return (
-		<div className="p-4 max-w-2xl mx-auto">
-			<h1 className="text-xl font-bold mb-4">Nowa umowa</h1>
-			<ContractForm />
-		</div>
+		<PageContainer>
+			<PageHeader
+				title="Create New Contract"
+				description="Add a new contract to your portfolio"
+				action={
+					<Link href="/contracts">
+						<Button variant="outline" size="sm">
+							<svg
+								className="w-4 h-4 mr-2"
+								fill="none"
+								stroke="currentColor"
+								viewBox="0 0 24 24"
+							>
+								<path
+									strokeLinecap="round"
+									strokeLinejoin="round"
+									strokeWidth={2}
+									d="M15 19l-7-7 7-7"
+								/>
+							</svg>
+							Back to Contracts
+						</Button>
+					</Link>
+				}
+			/>
+			<div className="max-w-2xl">
+				<ContractForm />
+			</div>
+		</PageContainer>
 	);
 }