fix: use correct connection name in getFieldsFromConn

[stonecool]

Description

Fixes a bug where table field generation returns empty fields array when using multiple database connections with non-default connection.

Problem

When using adm generate with a non-default database connection (e.g. connection = "business"), the generated table model file contains no fields.

The issue is in getFieldsFromConn() function in plugins/admin/modules/tools/generator.go line 444.

Root Cause

// Before (bug):
columnsModel, _ := db.WithDriver(conn).Table(table).ShowColumnsWithComment(conn.GetConfig(connName).Name)`WithDriver(conn)

always sets sql.conn = "default" internally, ignoring the connName parameter. This causes the query to execute on the wrong database connection.

Solution

Use WithDriverAndConnection(connName, conn) instead to respect the specified connection name:

// After (fixed):
columnsModel, _ := db.WithDriverAndConnection(connName, conn).Table(table).ShowColumns()

Testing

Tested with the following configuration:

[database]
driver = mysql
name = goadmin

[database.business]
driver = mysql
name = business