feat: add sovran_systemsOS.caddy.extraVirtualHosts NixOS option

Agent-Logs-Url: https://github.com/naturallaw777/staging_alpha/sessions/e966dd20-b74e-4ec5-b4db-68aa06129162

Co-authored-by: naturallaw777 <99053422+naturallaw777@users.noreply.github.com>

modules/core/caddy.nix

@@ -2,6 +2,7 @@
 
 let
   exposeBtcpay = config.sovran_systemsOS.web.btcpayserver;
+  extraVhosts = config.sovran_systemsOS.caddy.extraVirtualHosts;
 in
 {
   services.caddy = {
@@ -170,6 +171,11 @@ EOF
   encode gzip zstd
 }
 EOF
+
+      # ── Custom vhosts from custom.nix ──────────────
+      cat >> /run/caddy/Caddyfile <<'CUSTOM_VHOSTS_EOF'
+${extraVhosts}
+CUSTOM_VHOSTS_EOF
     '';
   };
 }