fix(core): increase PostgreSQL and MySQL connection pool size

- PostgreSQL: 4 -> 10 connections
- MySQL: 3 -> 10 connections

Fixes #1516

crates/dbx-core/src/db/mysql.rs

@@ -376,7 +376,7 @@ pub async fn connect_with_ca_cert(
     ca_cert_path: Option<&str>,
     fallback_timeout: Duration,
 ) -> Result<MySqlPool, String> {
-    connect_with_ca_cert_and_pool_limit(url, ca_cert_path, fallback_timeout, 3).await
+    connect_with_ca_cert_and_pool_limit(url, ca_cert_path, fallback_timeout, 10).await
 }
 
 pub async fn connect_with_ca_cert_and_pool_limit(

crates/dbx-core/src/db/postgres.rs

@@ -590,7 +590,7 @@ pub async fn connect(url: &str, fallback_timeout: Duration) -> Result<Pool, Stri
             mgr_config,
         );
         let pool = Pool::builder(mgr)
-            .max_size(4)
+            .max_size(10)
             .runtime(Runtime::Tokio1)
             .wait_timeout(Some(timeout))
             .build()