fix(inbound): explain how to unlock fallbacks on the inbound form (#5014)

The fallbacks card only renders for VLESS/Trojan over RAW with TLS or
Reality security, and a new inbound starts at security=none — so the Add
Inbound page looked like it had lost fallback support entirely. Show an
inline hint in that state pointing at the Security tab.

internal/web/translation/id-ID.json

@@ -282,7 +282,8 @@
         "quickAdded": "Menambahkan {n} fallback",
         "quickAddedNone": "Tidak ada inbound baru yang memenuhi syarat",
         "routesWhen": "Diarahkan ketika",
-        "defaultCatchAll": "Default — menangkap apa pun lainnya"
+        "defaultCatchAll": "Default — menangkap apa pun lainnya",
+        "needsTls": "Fallback tersedia setelah memilih TLS atau Reality di tab Keamanan (hanya VLESS/Trojan melalui RAW)."
       },
       "protocol": "Protokol",
       "port": "Port",