feat: support upto 15 days of listings

- change default timespan to 6
- parallize tv listing chunks

special thanks to @majortom9
https://github.com/jef/zap2xml/issues/41#issuecomment-3092418305

src/config.ts

@@ -9,7 +9,7 @@ export const config = {
   timespan:
     process.env["TIMESPAN"] ||
     process.argv.find((arg) => arg.startsWith("--timespan="))?.split("=")[1] ||
-    "3",
+    "6",
   country:
     process.env["COUNTRY"] ||
     process.argv.find((arg) => arg.startsWith("--country="))?.split("=")[1] ||