fix some problems with url origins in web (denoising works there too)

proxy/src/main.rs

@@ -39,6 +39,7 @@ fn default_cert_alt_names() -> Vec<String> {
 #[derive(Debug, Deserialize, Serialize)]
 struct Config {
     public_url: Url,
+    proxy_url: Option<Url>,
     https_listen_address: SocketAddr,
     http_listen_address: Option<SocketAddr>,
     cert_path: Option<PathBuf>,
@@ -82,7 +83,10 @@ async fn main() -> Result<()> {
         .map_err(|e| anyhow!("could not install crypto provider {e:?}"))?;
 
     let mut client_config = ClientConfig {
-        proxy_url: Some(server_config.public_url.join("proxy")?.to_string()),
+        proxy_url: match &server_config.proxy_url {
+            Some(url) => Some(url.to_string()),
+            None => Some(server_config.public_url.join("proxy")?.to_string()),
+        },
         status_url: Some(server_config.public_url.join("status")?.to_string()),
         cert_hash: None,
         any_server: false,