Add emote management UI at /manage

Adds a server-side HTML management page and supporting backend for
full CRUD on emotes. The /manage prefix is kept isolated so an auth
middleware can be applied to it later without touching other routes.

- GET /manage — serves the management UI (add, edit, delete, search)
- GET /manage/emotes — admin JSON endpoint with uuid and alias included
- AdminEmoteResponse model for the expanded admin representation
- Client-side search filters by name or alias as you type

src/main.rs

@@ -60,6 +60,8 @@ async fn main() {
         .route("/emotes", post(routes::emotes::create_emote))
         .route("/emotes/{uuid}", put(routes::emotes::update_emote))
         .route("/emotes/{uuid}", delete(routes::emotes::delete_emote))
+        .route("/manage", get(routes::manage::manage_root))
+        .route("/manage/emotes", get(routes::manage::list_admin_emotes))
         .layer(TraceLayer::new_for_http())
         .with_state(state);