Add Health Check dashboard to admin sidebar

[Bodge-IT]

Register the Healthcheck cpanel dashboard with menu preset, mod_submenu instance, language strings, and base SQL for both MySQL and PostgreSQL.

Pull Request for Issue # .

Summary
Adds the Health Check dashboard to the Joomla administrator sidebar, providing the infrastructure for future healthcheck plugins and modules.

Changes

• Menu preset (healthcheck.xml): new preset for the Healthcheck dashboard sidebar
• Sidebar menu item (default.xml): "Healthcheck" entry before System, linking to com_cpanel&dashboard=healthcheck
• Language strings (mod_menu.ini): MOD_MENU_HEALTHCHECK, MOD_MENU_HEALTHCHECK_DASHBOARD, MOD_MENU_HEALTHCHECK_PARENT_OVERVIEW
• Module instance (MySQL + PostgreSQL base.sql): mod_submenu at position cpanel-healthcheck with preset healthcheck
• Asset registration (MySQL + PostgreSQL base.sql): nested set entry for the new module, with all subsequent lft/rgt values shifted accordingly

Test plan

• Fresh install should show "Healthcheck" in the admin sidebar between Users and System
• Clicking it should load an empty cpanel dashboard at ?option=com_cpanel&view=cpanel&dashboard=healthcheck
• The cpanel-healthcheck module position is ready for future healthcheck modules

Expected result AFTER applying this Pull Request

You have a nice Healthcheck menu and dash.

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed