aerodatabox: add browser User-Agent, fixes 403 from Cloudflare/RapidAPI gateway

aerodatabox.py

@@ -100,8 +100,16 @@ def lookup_gate_times(flight_number: str, flight_date: date) -> dict | None:
         f"{BASE_URL}/flights/number/{cleaned}/{flight_date.isoformat()}"
         "?dateLocalRole=Both&withAircraftImage=false&withLocation=false"
     )
+    # A default urllib request (no User-Agent) gets HTTP 403 from AeroDataBox's
+    # Cloudflare-fronted gateway even with a perfectly valid, subscribed key -
+    # confirmed live, side by side, same key/URL: bare urllib -> 403, same
+    # request + this UA -> 200 with real data. See config.BROWSER_USER_AGENT.
     req = urllib.request.Request(
-        url, headers={"x-rapidapi-key": config.AERODATABOX_API_KEY}
+        url,
+        headers={
+            "x-rapidapi-key": config.AERODATABOX_API_KEY,
+            "User-Agent": config.BROWSER_USER_AGENT,
+        },
     )
     try:
         with urllib.request.urlopen(req, timeout=20) as resp: