Leave a Markdown mail component's classes to the mail theme in the design guard

A mail component is drawn by the mail theme, not by the application's
CSS entry, and the theme's classes share Tailwind's names: ReStride's
`x-mail::sessions` wraps its table in `<div class="table">`, the class
the package's own mail theme styles, and the guard reported it as
Tailwind's `display: table`. A view under a path `mail.markdown.paths`
names (Laravel's `resources/views/vendor/mail` by default) now skips
family (i) and the breakpoint, scale, palette and colour-value checks;
its icon names, the directives in its component tags, forbidColours()
and forbid() are still read. A mail theme stylesheet under that path,
which has to write literal values, is left out of check (iii) and of
the exempt classes, so its `.table` no longer hides `table` in the
application's other views either. The guard's docblock, the README and
the skill's "Testing the design" say so; a fixture test reads the same
mail view and theme with and without the path configured.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

UPGRADE.md

@@ -9,6 +9,13 @@
   it in the layout, `toggle()` opens and closes the modal rail (`show()`, `hide()`) instead of
   changing a choice nothing draws there. A shortcut that pressed the rail's menu button to get this
   can call `$store.rail.toggle()` again.
+- **`DesignGuard`** no longer reads a Markdown mail component's classes as Tailwind: a view under
+  `mail.markdown.paths` (`resources/views/vendor/mail` by default) is drawn by the mail theme, whose
+  `table`, `button` and `panel` share Tailwind's names, so only its icon names, the directives in
+  its component tags and the application's own bans are checked there. A mail theme stylesheet
+  under that path is no longer checked for literal values, and its classes no longer exempt the
+  same names in the application's other views. A filter an application wrote around such a
+  finding can go.
 - **`DesignGuard`** reports a colour utility on a colour the application's own Tailwind theme
   named (`bg-brand`, `text-sport-run`, `from-brand`, `border-l-zone-4`, `bg-brand/8`) in a class
   list, with `var(--…)` of the application's own as its replacement, unless the application's