feat: Implement external MySQL integration for LMS enrollments and grade synchronization, including external_id and tipo_nota support.

services/lms-service/src/external_db.rs

@@ -0,0 +1,26 @@
+use sqlx::{MySql, Pool};
+use std::env;
+
+pub type MySqlPool = Pool<MySql>;
+
+pub async fn init_mysql_pool() -> Option<MySqlPool> {
+    if let Ok(url) = env::var("MYSQL_DATABASE_URL") {
+        match sqlx::mysql::MySqlPoolOptions::new()
+            .max_connections(5)
+            .connect(&url)
+            .await
+        {
+            Ok(pool) => {
+                tracing::info!("Connected to external MySQL database");
+                Some(pool)
+            }
+            Err(e) => {
+                tracing::error!("Failed to connect to external MySQL database: {}", e);
+                None
+            }
+        }
+    } else {
+        tracing::info!("MYSQL_DATABASE_URL not set, skipping external database integration");
+        None
+    }
+}