Add a colour spec choice to material:scheme

The scheme script always generated with material-color-utilities' 2025 spec.
An application whose palette was generated with M3's original 2021 colour
(ReStride) could not reproduce it. The script now takes `spec` ('2025' by
default, or '2021') and refuses anything else, and the command takes
`--spec`, validated before Node runs.

Colour profiles may set their own `spec`, `success`, `warning` and `info`;
without them the command's options apply. The stylesheet header writes out
every option that differs from its default, so the recorded command
regenerates the file, and a profile whose spec differs from the header's
names it. Default output is byte-for-byte unchanged.

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

@@ -44,7 +44,7 @@ The scheme is generated, never hand-edited. Regenerate it with the seed and vari
 php artisan material:scheme "#4f46e5" --variant=tonal-spot
 ```
 
-Variants: `tonal-spot` (M3's default), `vibrant`, `expressive`, `neutral`, `fidelity`, `content`, `monochrome`, `rainbow`, `fruit-salad`. `--success`, `--warning` and `--info` set the source of the state colours; `--contrast` goes from -1 to 1. The command also writes `material-scheme.json` beside the stylesheet.
+Variants: `tonal-spot` (M3's default), `vibrant`, `expressive`, `neutral`, `fidelity`, `content`, `monochrome`, `rainbow`, `fruit-salad`. `--spec` is the colour spec: `2025` (default, M3 Expressive) or `2021` (M3's original colour — keep it for a palette generated before Expressive; the library itself uses 2021 for variants 2025 does not define, and the header records the spec actually used). `--success`, `--warning` and `--info` set the source of the state colours; `--contrast` goes from -1 to 1. The header of the stylesheet records the whole command, every option that differs from its default included. The command also writes `material-scheme.json` beside the stylesheet.
 
 ### Colour profiles
 
@@ -62,6 +62,7 @@ An installation that switches between several schemes lists them in `config/live
 php artisan material:scheme
 ```
 
+- Each profile: `seed`, and optionally `label` (default: the name as a headline), `variant` (default `tonal-spot`), `contrast` (default 0), `spec`, `success`, `warning`, `info` (for these four, without the key the command's `--spec`, `--success`, `--warning`, `--info` or their defaults apply).
 - Names are lowercase letters, digits and dashes. Regenerate after changing the list; only generated profiles exist for the picker, the resolver and the stylesheet.
 - The application says which profile is active, once, in a service provider. The closure runs every time a colour is drawn (head script, mail, error page), so it may read the database; a name that is not a generated profile, or a closure that throws, falls back to the default: