case 4732 - trusted reverse proxies setting

New config setting AYANOVA_TRUSTED_PROXIES (IP addresses or CIDR networks)
for reverse proxies on another computer: their X-Forwarded-For is used, a
chain of trusted proxies is followed, invalid entries are warned at boot.
X-Forwarded-For from a proxy that is not trusted logs one warning per server
start naming the proxy's address. Without the setting nothing changes (only
a loopback proxy is trusted). Shown in server info; manual page, Linux install
note, changelog. F6 follow-up recorded.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/AyaNova/util/ServerBootConfig.cs

@@ -107,6 +107,8 @@ namespace AyaNova.Util
 
         //SECURITY
         internal static string AYANOVA_SET_SUPERUSER_PW { get; set; }
+        //case 4732: reverse proxies on other computers whose X-Forwarded-For is trusted (addresses or networks, comma separated)
+        internal static string AYANOVA_TRUSTED_PROXIES { get; set; }
 
         //EMAIL
         //case 4724: the SMTP server's certificate is checked unless this is set (a mail server with a self-signed or internal certificate)
@@ -189,6 +191,8 @@ namespace AyaNova.Util
             //backdoor back door password superuser reset
             AYANOVA_SET_SUPERUSER_PW = config.GetValue<string>("AYANOVA_SET_SUPERUSER_PW");
 
+            AYANOVA_TRUSTED_PROXIES = config.GetValue<string>("AYANOVA_TRUSTED_PROXIES");
+
             //REPORT RENDERING
 
             //RENDER OVERRIDE URL FOR CORS ISSUES BEHIND IIS (case 4398)