Add product variants API, deployment scripts, and documentation

- Add Node.js variant-api server with PostgreSQL integration
- Add new utility scripts for system verification and website status
- Update CI/CD workflow configuration
- Add color variant solution documentation
- Add product variants JavaScript support
- Update gitignore for new build artifacts

variant-api/node_modules/postgres-interval/index.d.ts

@@ -0,0 +1,20 @@
+declare namespace PostgresInterval {
+  export interface IPostgresInterval {
+    years?: number;
+    months?: number;
+    days?: number;
+    hours?: number;
+    minutes?: number;
+    seconds?: number;
+    milliseconds?: number;
+
+    toPostgres(): string;
+
+    toISO(): string;
+    toISOString(): string;
+  }
+}
+
+declare function PostgresInterval(raw: string): PostgresInterval.IPostgresInterval;
+
+export = PostgresInterval;