Take disabled off the FAB, and fix its extended metrics

M3 is explicit twice over — never disable a FAB, remove it instead — and the
prop painted the full disabled treatment with nothing warning against it. It is
gone; hiding the FAB is the documented answer. The extended FAB's icon-to-label
gap goes to M3's 16dp at md and 20dp at lg, the small one takes the baseline's
80dp minimum width, and the root gains a `data-fab` hook for a place that draws
a nested FAB its own way. Plan step 18, actions.md ACT-08, ACT-16, ACT-31.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/views/components/fab.blade.php

@@ -12,6 +12,14 @@
      The glyph is filled, not outlined: M3 says so twice, in the FAB's anatomy and again in its
      guidelines ("icon should be filled (not outlined) and unambiguous").
 
+     There is no `disabled`: M3 says never to disable a FAB — "if its action is unavailable,
+     remove the FAB entirely instead" — so hide it (`@if`), or leave it out of the render, rather
+     than greying it out. A form-submit FAB that must not be pressed twice takes the caller's own
+     `wire:loading.attr="disabled"`.
+
+     `data-fab` marks the root, so a place a FAB sits in can draw it its own way: a navigation
+     rail flattens a nested FAB to elevation 0.
+
      Sizes, corners and elevation from FabBaseline/Medium/LargeTokens and ExtendedFab*Tokens
      (androidx Compose Material 3, Apache-2.0). --}}
 
@@ -24,7 +32,6 @@
     'link' => null,
     'external' => false,
     'tooltip' => null,
-    'disabled' => false,
     'type' => 'button',
 ])
 
@@ -39,7 +46,7 @@
         : ['primary' => 'bg-primary-container text-on-primary-container', 'secondary' => 'bg-secondary-container text-on-secondary-container', 'tertiary' => 'bg-tertiary-container text-on-tertiary-container'][$color];
 
     $dimensions = $extended
-        ? ['sm' => 'h-14 min-w-14 gap-2 px-4 rounded-corner-lg type-title-md', 'md' => 'h-20 min-w-20 gap-3 px-[26px] rounded-corner-lg-increased type-title-lg', 'lg' => 'h-24 min-w-24 gap-4 px-7 rounded-corner-xl type-headline-sm'][$size]
+        ? ['sm' => 'h-14 min-w-20 gap-2 px-4 rounded-corner-lg type-title-md', 'md' => 'h-20 min-w-20 gap-4 px-[26px] rounded-corner-lg-increased type-title-lg', 'lg' => 'h-24 min-w-24 gap-5 px-7 rounded-corner-xl type-headline-sm'][$size]
         : ['sm' => 'size-14 rounded-corner-lg', 'md' => 'size-20 rounded-corner-lg-increased', 'lg' => 'size-24 rounded-corner-xl'][$size];
 
     $iconSize = ['sm' => 'size-6', 'md' => 'size-7', 'lg' => 'size-8'][$size];
@@ -52,7 +59,6 @@
             'shadow-elevation-3 hover:shadow-elevation-4 transition-[box-shadow,background-color,color] duration-(--md-sys-motion-effects-fast-duration) ease-effects-fast',
             $dimensions,
             $colours,
-            'disabled:cursor-not-allowed disabled:bg-on-surface/10 disabled:text-on-surface/38 disabled:shadow-none',
         ])
         ->merge(array_filter([
             'href' => $isLink ? $link : null,
@@ -60,7 +66,8 @@
             'rel' => $isLink && $external ? 'noopener' : null,
             'wire:navigate' => $isLink && ! $external && ! $attributes->has('wire:navigate') ? true : null,
             'type' => $isLink ? null : $type,
-            'disabled' => ! $isLink && $disabled ? true : null,
+            // The hook a place uses to draw a nested FAB its own way: a rail flattens it to 0dp.
+            'data-fab' => true,
             'aria-label' => ! $extended && ! $attributes->has('aria-label') ? $tooltip : null,
             'style' => $anchor ? "anchor-name: {$anchor}" : null,
         ], fn ($value): bool => $value !== null));