radio: public read-only tracker for Opa (NL/EN toggle, bigger type and tap targets)

Visitors see frequencies, banks, nets, ISS passes and the log without logging in; every
write stays owner-only (actions check the owner, hooks refuse non-GET). The public payload
drops reminder switches, log notes and inactive nets, and the page no longer shows the
observer coordinates (only "Gouda"). Dutch/English toggle (?lang, cookie, Accept-Language,
NL fallback). Larger fonts, high-contrast labels and 44px+ controls for phones and tablets;
radio listed as public (no lock) and in the sitemap; banks CSV public.

src/routes/sitemap.xml/+server.ts

@@ -31,6 +31,7 @@ const staticPaths = [
 	'/stats/kor/overview',
 	'/trackers/books',
 	'/trackers/ai',
+	'/trackers/radio',
 	'/trackers/spotting',
 	'/trackers/cars',
 	'/trackers/cars/brands',