Fix favicon (real icon, not an unrelated orange circle) + stack encouragements with the submit button

favicon.svg was a plain solid circle, unrelated to the actual brand
mark - replaced with the real single-arch icon (matching
infrastructure/assets/icon-{light,dark}.svg), split into two
prefers-color-scheme-scoped files rather than one SVG with an embedded
@media query - the latter doesn't reliably re-evaluate via <link> on
Safari/iOS (confirmed by prior real-device testing on the Gitea side,
see gitea-head.tmpl).

Encouragements used to render right after the description, separated
from the actual submit button by the whole features/requirements
block - moved them into the same wrapper as the form, directly above
the button, so reassurance text and the call to action read together.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/main.rs

@@ -117,7 +117,8 @@ async fn main() -> anyhow::Result<()> {
         "{}/{}",
         leptos_options.site_root, leptos_options.site_pkg_dir
     );
-    let favicon_path = format!("{}/favicon.svg", leptos_options.site_root);
+    let favicon_light_path = format!("{}/favicon-light.svg", leptos_options.site_root);
+    let favicon_dark_path = format!("{}/favicon-dark.svg", leptos_options.site_root);
     let fonts_dir = format!("{}/fonts", leptos_options.site_root);
 
     let app = Router::new()
@@ -130,7 +131,8 @@ async fn main() -> anyhow::Result<()> {
         .route("/automation/kv/{bucket}", get(content::automation_kv_handler))
         .nest_service("/pkg", ServeDir::new(pkg_dir))
         .nest_service("/fonts", ServeDir::new(fonts_dir))
-        .route_service("/favicon.svg", ServeFile::new(favicon_path))
+        .route_service("/favicon-light.svg", ServeFile::new(favicon_light_path))
+        .route_service("/favicon-dark.svg", ServeFile::new(favicon_dark_path))
         .leptos_routes_with_context(
             &state,
             routes,