feat: README, config.example, turnstile integration, exchange rate, auth utils refactor

src/queue/handler/task.rs

@@ -4,7 +4,7 @@ use asynq::error::Result;
 use asynq::task::Task;
 
 use crate::config::Config;
-use crate::queue::service::task::QuotaTaskLogic;
+use crate::queue::service::task::{QuotaTaskLogic, RateLogic};
 use crate::repository::Repositories;
 
 pub async fn quota_task(task: Task, repos: Arc<Repositories>, config: Arc<Config>) -> Result<()> {
@@ -13,3 +13,12 @@ pub async fn quota_task(task: Task, repos: Arc<Repositories>, config: Arc<Config
         .await
         .map_err(|e| asynq::error::Error::other(e.to_string()))
 }
+
+/// Fetch the current exchange rate and persist it.
+/// Scheduled daily at 01:00 by the scheduler (mirrors `rateLogic.go`).
+pub async fn rate_task(_task: Task, repos: Arc<Repositories>, config: Arc<Config>) -> Result<()> {
+    RateLogic::new(repos, config)
+        .execute()
+        .await
+        .map_err(|e| asynq::error::Error::other(e.to_string()))
+}