Add hint-class to the group and icon-class to menu items

<x-group hint-class> adds classes to the hint, as the text fields'
hint-class does, and a validation message still replaces the hint.
<x-menu-item icon-class> adds classes to the leading icon, for an icon
whose colour means something of its own, such as a sport's glyph.

A colour class there has to win over the component's own colour, and
which of two colour utilities wins depends on the order Tailwind emits
them (text-error comes before text-on-surface-variant). So when either
prop is given, the component's own colour is written with a :where()
variant that carries no specificity, as the fields' hint colour sits
in the components layer. A disabled item's icon stays disabled. Without
the props the markup is unchanged. The skill now also lists the fields'
hint-class, which it had left out.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RHoXZSHc8gGpZjFmA5fPc2

resources/boost/skills/livewire-material-development/SKILL.md

@@ -244,7 +244,7 @@ M3's plain tooltip, standalone around any trigger: `<x-tooltip text="Copy link"
 </x-menu>
 ```
 
-`<x-menu>`: `trigger` slot (its first button or link becomes the menu button, and the menu hangs on that button — a `position: fixed` trigger such as `<x-button fab>` carries it along, and a menu with no room flips to the other side, end or both), `label`, `position` (`bottom-start` default, `bottom-end`, `top-start`, `top-end`), `vibrant`. `<x-menu-item>`: `label`, `icon`, `icon-right`, `description`, `shortcut`, `link`, `external`, `selected` (makes it a `menuitemcheckbox`), `disabled`, `keep-open`. Choosing an item closes the menu unless `keep-open`. Keyboard: arrows, Home, End, a letter, Escape (focus returns to the trigger), Tab.
+`<x-menu>`: `trigger` slot (its first button or link becomes the menu button, and the menu hangs on that button — a `position: fixed` trigger such as `<x-button fab>` carries it along, and a menu with no room flips to the other side, end or both), `label`, `position` (`bottom-start` default, `bottom-end`, `top-start`, `top-end`), `vibrant`. `<x-menu-item>`: `label`, `icon`, `icon-class` (classes for the leading icon; a colour there paints it, a selected item's too, but not a disabled one's — `icon-class="text-sport-run"`), `icon-right`, `description`, `shortcut`, `link`, `external`, `selected` (makes it a `menuitemcheckbox`), `disabled`, `keep-open`. Choosing an item closes the menu unless `keep-open`. Keyboard: arrows, Home, End, a letter, Escape (focus returns to the trigger), Tab.
 
 ### `<x-button-group>`
 
@@ -262,7 +262,7 @@ A choice between a few options as a connected button group of native radios (che
 ]" hint="Recipients lose access after that" />
 ```
 
-Props: `label`, `hint`, `name` (required with `x-model`), `options`, `option-value` (`id`), `option-label` (`name`), `option-icon` (`icon`), `size`, `variant` (`tonal`, `filled`, `outlined`), `multiple`, `inline` (intrinsic width instead of sharing the row). A validation error for the bound property replaces the hint.
+Props: `label`, `hint`, `hint-class` (classes for the hint, as on the fields; a colour there paints it), `name` (required with `x-model`), `options`, `option-value` (`id`), `option-label` (`name`), `option-icon` (`icon`), `size`, `variant` (`tonal`, `filled`, `outlined`), `multiple`, `inline` (intrinsic width instead of sharing the row). A validation error for the bound property replaces the hint.
 
 ### `<x-split-button>`
 
@@ -535,7 +535,7 @@ A one-column grid of fields with an `actions` slot at the foot (the slot takes i
 
 ### `<x-field>`, `<x-input>`, `<x-password>`, `<x-textarea>`, `<x-select>`, `<x-file>`
 
-M3 text fields. `variant`: `outlined` or `filled`; without it, `config('livewire-material.fields.variant')` (`outlined`). All take `label`, `hint`, `variant`, and read their errors from the bag under the `wire:model` name, or the `name` in a plain form (`photos[]` → `photos`, `address[city]` → `address.city`); the error replaces the hint and sets `aria-invalid`. `class` lands on the field's outer element (margins, widths); every other attribute (`wire:model`, `type`, `required`, `readonly`, `autocomplete`) reaches the control. Never pass `placeholder` expecting it to show while a label rests in the field: it shows once the field has focus.
+M3 text fields. `variant`: `outlined` or `filled`; without it, `config('livewire-material.fields.variant')` (`outlined`). All take `label`, `hint`, `variant` (and all but `<x-file>` a `hint-class`, classes added to the hint: `hint-class="text-warning"`), and read their errors from the bag under the `wire:model` name, or the `name` in a plain form (`photos[]` → `photos`, `address[city]` → `address.city`); the error replaces the hint and sets `aria-invalid`. `class` lands on the field's outer element (margins, widths); every other attribute (`wire:model`, `type`, `required`, `readonly`, `autocomplete`) reaches the control. Never pass `placeholder` expecting it to show while a label rests in the field: it shows once the field has focus.
 
 - `<x-input>`: `icon`, `icon-right`, `prefix`, `suffix`, `clearable`, `copyable` (copies the value, confirms with a snackbar), `size` (`sm` 40px, `xs` 32px — for unlabelled toolbar controls; give them `aria-label`), `mono`.
 - `<x-password>`: a reveal button; `icon`, `size`.