Avoid repeated warm request dispatch work

src/wasm/backend.cpp

@@ -68,6 +68,10 @@ static String wasm_backend_ensure_started(Request* context)
 	}
 
 	g_wasm_worker = new WasmWorker(wc);
+	// Server configuration is finalized before render workers start. Retain one
+	// native tree so per-request UCEB encoding can reference it without rebuilding
+	// dozens of identical nodes; the guest still decodes it into fresh state.
+	g_wasm_worker->server_config_context = cfg;
 	g_wasm_init_error = g_wasm_worker->init();
 	if(g_wasm_init_error == "")
 		g_wasm_init_error = wasm_worker_prepare(*g_wasm_worker);
@@ -156,7 +160,7 @@ String wasm_backend_serve(Request& request, const String& entry_unit, const Stri
 			ctx[key][entry.first] = entry.second;
 	};
 	if(request.server)
-		copy_map(request.server->config, "server_config");
+		ctx["server_config"].set_reference(&g_wasm_worker->server_config_context);
 	copy_map(request.params, "params");
 	copy_map(request.get, "get");
 	copy_map(request.post, "post");