fix: Correct server.ts class syntax and static method placement

src/server.ts

@@ -71,13 +71,15 @@ export class WebhookServer {
   }
 }
 
-  static start() {
-    if (process.env.NODE_ENV !== 'test') {
-      const server = Bun.serve({
-        port: PORT,
-        fetch: WebhookServer.handleRequest,
-      });
-      console.log(`Server running on port ${PORT}`);
-      return server;
-    }
+}
+
+static start() {
+  if (process.env.NODE_ENV !== 'test') {
+    const server = Bun.serve({
+      port: PORT,
+      fetch: WebhookServer.handleRequest,
+    });
+    console.log(`Server running on port ${PORT}`);
+    return server;
   }
+}