Axismundi Navigation Icons

Axismundi Navigation Icons is an authoring plugin: it adds a “Navigation Icon”
panel to the block sidebar for navigation items, where you type a Material
Symbols ligature name (e.g. home, article, category, sell, tag,
folder). The icon is inserted before the item label.

Supported blocks:

• Navigation Link (core/navigation-link) — also covers the page / post /
  category / tag / custom link variants, which are the same block. Page links
  default to pages, category links to category, and tag links to label
  when no custom icon is authored.
• Submenu (core/navigation-submenu).
• Home Link (core/home-link) — shows the home icon by default, with a
  “Show home icon” toggle to opt out.
• Page List (core/page-list) — shows the pages icon by default for generated
  page items when the list is placed inside a Navigation block, with a “Show item
  icons” toggle to opt out.

A core/navigation style variation, “Vertical item”, stacks the icon above the
label (M3 Navigation Bar / Rail vertical item) and moves the active indicator
onto a 56×32 icon slot; the unstyled default keeps the icon beside the label.

The Axismundi theme keeps the Material Design 3 navigation spec and the item
baseline (pill, state layer, active indicator), the Material Symbols font
(registered in theme.json) and the .material-symbols-outlined box contract
(icons.css). This plugin owns the icon data and its insertion, the item-layout
style variation, the front-end icon-click delegation, and — for the items it
restructures — the submenu disclosure arrow.