# Legacy Menu Code Navigation Design

## Problem

Legacy frontend page designs may store a business menu code such as
`announcements` in `menu_code` while the page code is
`announcement_list_page`. These records do not declare a navigation level or
parent menu.

The current generator treats every differing `menu_code` as a parent menu
code. It therefore renders an artificial directory named `announcements`
instead of the page's display name.

## Design

Menu hierarchy must be driven only by explicit navigation metadata:

- A page is secondary when `navigation.menuLevel` is `secondary`.
- A page is secondary when `navigation.parentMenuCode` is present.
- Otherwise the page is a primary menu, even when `menu_code` differs from
  `page_code`.

The existing `menu_code` remains the primary group's stable key. Its display
label continues to come from `navigation.menuName`, then `page_name`, then
`page_code`.

## Compatibility

Explicit directory and secondary-menu configurations are unchanged. No
database migration is required.

## Verification

Add a generator regression test using a page whose `menu_code` differs from
its `page_code` and whose layout has no navigation hierarchy metadata. The
rendered application must contain one clickable primary menu using the page
name and must not contain an artificial directory using the menu code.