fix(opencode): allow delete button for all providers in additive mode

OpenCode uses additive mode where the main "Remove" button removes from
live config, while the delete button should delete from database. The
delete button should always be enabled for OpenCode providers.

src/components/providers/ProviderActions.tsx

@@ -152,8 +152,8 @@ export function ProviderActions({
 
   const buttonState = getMainButtonState();
 
-  // OpenCode 模式下删除按钮的行为不同（主按钮已处理移除功能）
-  const canDelete = isOpenCodeMode ? !isInConfig : !isCurrent;
+  // OpenCode 模式下删除按钮始终可用（主按钮"移除"是从 live 配置移除，删除是从数据库删除）
+  const canDelete = isOpenCodeMode ? true : !isCurrent;
 
   return (
     <div className="flex items-center gap-1.5">