feat: hotel radio widget (client-side, multi-station)

Adds a compact collapsible radio widget (top-left) that plays internet
radio streams with the HTML5 Audio API — no server/renderer changes.

- station list loaded from a JSON5 config file (loadGamedata: JSON + JSON5),
  shipped as radio-stations.json5.example so each hotel fills in its own
- shows the selected station + a dropdown (3 visible, scrolls if more) to
  switch; volume slider; animated equalizer + LIVE indicator
- first station autostarts quietly (5%) on load, with a resume-on-first-
  gesture fallback for browser autoplay policy

public/configuration/wheel-texts-it.example

@@ -9,5 +9,9 @@
     "soundboard.title": "Soundboard",
     "soundboard.empty": "Nessun suono disponibile",
     "soundboard.lastplayed": "Suonato da %user%",
-    "soundboard.room.setting.desc": "Permetti ai presenti di suonare effetti audio in questa stanza"
+    "soundboard.room.setting.desc": "Permetti ai presenti di suonare effetti audio in questa stanza",
+    "radio.title": "Radio",
+    "radio.empty": "Nessuna stazione",
+    "radio.error": "Impossibile caricare le stazioni",
+    "radio.stop": "Stop"
 }