feat: auto-fallback to Clash proxy on scheduled subscription updates; refactor fallback logic and add request timeout

src/services/types.d.ts

@@ -207,6 +207,7 @@ interface IProfileOption {
   with_proxy?: boolean;
   self_proxy?: boolean;
   update_interval?: number;
+  timeout_seconds?: number;
   danger_accept_invalid_certs?: boolean;
   merge?: string;
   script?: string;