fix(server): signup/signin logic (#4008)

apps/core/src/components/affine/auth/sign-in.tsx

@@ -21,6 +21,8 @@ function validateEmail(email: string) {
   return emailRegex.test(email);
 }
 
+const INTERNAL_BETA_URL = `https://community.affine.pro/c/insider-general/`;
+
 function handleSendEmailError(
   res: SignInResponse | undefined,
   pushNotification: (notification: Notification) => void
@@ -32,6 +34,13 @@ function handleSendEmailError(
       type: 'error',
     });
   }
+  if (res?.status === 403 && res?.url === INTERNAL_BETA_URL) {
+    pushNotification({
+      title: 'Sign up error',
+      message: `You don't have early access permission\nVisit ${INTERNAL_BETA_URL} for more information`,
+      type: 'error',
+    });
+  }
 }
 
 export const SignIn: FC<AuthPanelProps> = ({