Parallelize worker batch processing

src/config.rs

@@ -12,6 +12,8 @@ pub struct Config {
 
     pub redis_url: String,
 
+    pub worker_concurrency: u32,
+
     pub jwt_secret: String,
     pub jwt_expiry_hours: i64,
 
@@ -60,6 +62,12 @@ impl Config {
         let redis_url = env_string("REDIS_URL")
             .ok_or_else(|| AppError::new(ErrorCode::InvalidRequest, "缺少环境变量 REDIS_URL"))?;
 
+        let worker_concurrency = env_u32("WORKER_CONCURRENCY").unwrap_or_else(|| {
+            std::thread::available_parallelism()
+                .map(|v| v.get() as u32)
+                .unwrap_or(4)
+        });
+
         let jwt_secret = env_string("JWT_SECRET")
             .ok_or_else(|| AppError::new(ErrorCode::InvalidRequest, "缺少环境变量 JWT_SECRET"))?;
         let jwt_expiry_hours = env_i64("JWT_EXPIRY_HOURS").unwrap_or(168);
@@ -103,6 +111,7 @@ impl Config {
             database_url,
             database_max_connections,
             redis_url,
+            worker_concurrency,
             jwt_secret,
             jwt_expiry_hours,
             api_key_pepper,