houses: keep Kamernet to the Gouda region (small-city pages are padded with listings from all over NL), share GOUDA_REGION

src/lib/house-tracker/address.ts

@@ -102,3 +102,19 @@ export function addressKeyFromText(
 	const { street, houseNumber } = splitAddress(text.replace(/,.*$/, ''));
 	return addressKey(street, houseNumber, city);
 }
+
+// The area Stan and Juhee are looking in (same list as the "Gouda area rentals" alert rule):
+// the page's default filter and the Kamernet scraper's scope.
+export const GOUDA_REGION = [
+	'gouda',
+	'waddinxveen',
+	'reeuwijk',
+	'moordrecht',
+	'nieuwerkerk-aan-den-ijssel',
+	'zevenhuizen',
+	'bodegraven',
+	'boskoop',
+	'oudewater',
+	'schoonhoven',
+	'haastrecht'
+] as const;