feat(theme-studio): show worst-case contrast for overlay faces

The five covered overlay faces (region, hl-line, highlight, lazy-highlight, isearch) now show the worst-case floor over their foreground set instead of one fg/bg pair. The cell starts with "worst:", names the limiting foreground by role and hex, then gives the ratio and a PASS/FAIL verdict, so a tint that clears the default text but fails the darkest token can't hide. The foreground set is the live syntax-token colors plus the default fg; the verdict is WCAG AA by default. Package and other UI rows keep their single-pair readout.

A syntax-color edit now repaints the covered faces, since their floors depend on the whole token palette, not just their own fg/bg. An out-of-scope face falls through to the single-pair cell, and a face whose set resolves empty reads "no fg set" rather than a bogus ratio.

Phase 4 of the palette-ramps spec. A #contrasttest browser gate pins the readout, the keyword-blue limiting case, the single-pair fallback, and the no-set message.

1 files changed, 1 insertions, 1 deletions

diff --git a/scripts/theme-studio/run-tests.sh b/scripts/theme-studio/run-tests.sh
index 2f074fe3..cd466f4b 100755
--- a/scripts/theme-studio/run-tests.sh
+++ b/scripts/theme-studio/run-tests.sh
@@ -53,7 +53,7 @@ CHROME=""
 for c in google-chrome-stable google-chrome chromium chromium-browser; do
   if command -v "$c" >/dev/null 2>&1; then CHROME="$c"; break; fi
 done
-HASHES="selftest cursortest readouttest deltatest oklchtest planetest locktest sorttest mocktest ramptest"
+HASHES="selftest cursortest readouttest deltatest oklchtest planetest locktest sorttest mocktest ramptest contrasttest"
 if [ "$NO_BROWSER" = 1 ]; then
   skip_msg "browser hash gates (--no-browser)"
 elif [ -z "$CHROME" ]; then