Fix redirect loop - remove automatic redirect

The automatic redirect was causing an infinite loop when accessing
auth.zzstoatzz.com/login. Now both domains serve the login page
directly without redirecting.

The OAuth flow will still use auth.zzstoatzz.com for the actual
authentication because that's configured in OAUTH_REDIRECT_BASE.

src/api/auth.rs

···
 
 /// Takes you to the login page
 #[get("/login")]
-pub async fn login(config: web::Data<config::Config>) -> Result<HttpResponse> {
-    // If we're using a separate auth domain, redirect to it
-    if config.uses_separate_auth_domain() {
-        let redirect_url = format!("{}/login", config.oauth_redirect_base);
-        return Ok(HttpResponse::Found()
-            .append_header(("Location", redirect_url))
-            .finish());
-    }
-
+pub async fn login() -> Result<impl Responder> {
+    // Don't redirect - just serve the login page
+    // The OAuth will use the correct redirect URL from config
     let html = LoginTemplate {
         title: "Log in",
         error: None,
     };
-    Ok(HttpResponse::Ok().body(html.render().expect("template should be valid")))
+    Ok(web::Html::new(
+        html.render().expect("template should be valid"),
+    ))
 }
 
 /// Logs you out by destroying your cookie on the server and web browser