Test check (iii) and fix two bugs it exposed in the application-CSS scan

Plan step 41(iii): fixtures/tests for every literal kind (colour, radius,
shadow, font size/weight, line height, letter spacing, easing, duration) and
an off-scale media query, plus material-scheme.css excluded by name and by
its generated header wherever it sits among the scanned paths. Also adds a
fixture proving Tailwind-shaped bare words in running prose are never read
as classes.

Two fixes found by writing the fixtures rather than only the implementation:
a directly-scanned .css file was also running through the Blade/PHP/JS checks
(the same file's `ease-in-out` in a `transition` value tripped the old scale
check a second time), so a CSS file is now check (iii)'s alone; and
`withoutTokenFunctions()` leaves a `var()`/`calc()` call's own name and
parentheses standing once its arguments are blanked, which
`isSafeLiteralValue()` did not yet recognise as the same "nothing to see
here" as an empty value.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

tests/Fixtures/design-guard/running-text.blade.php

@@ -0,0 +1,4 @@
+{{-- Running text is not a class list: none of Tailwind's bare-word utilities should be read out
+     of prose just because they share a spelling with one. --}}
+<p>This creates a grid of cards, in a flex layout that stays hidden below medium and stacks into a
+    block once the pane narrows. Nothing here truncates or grows, and the sample is not a table.</p>