fix(website): keep the signal yellow out of text, and drop a dead rule

Two defects I put in the plan, both caught in review.

.field-report-num painted the 01-06 chapter markers in --color-signal at
10px bold. That is 1.78:1 on the surface it sits on; the ATC theme split
the accent role precisely so this yellow stays fill-only. --color-accent
is the interactive ink at 14.86:1.

.pilot-eyebrow was kept on a false premise: I matched it as a substring of
.pilot-eyebrow-spaced / -tight, which /pilot-to-prod does use -- but those
are defined in pages.css. The bare class had no consumer left.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: blove

apps/website/src/styles/landing.css

@@ -350,11 +350,6 @@
   }
 }
 
-/* .pilot-eyebrow is the last survivor of the retired PilotBlock rules; the
- * rest went with the TeamsBlock rewrite. */
-.pilot-eyebrow {
-  margin-bottom: 16px;
-}
 
 /* RecentArticles — components/landing/RecentArticles.tsx */
 .recent-articles-rail {
@@ -2176,7 +2171,10 @@ a.preflight-row:hover .preflight-challenge {
   font-family: var(--font-mono);
   font-size: 10px;
   font-weight: 700;
-  color: var(--color-signal);
+  /* NOT --color-signal. The ATC theme split the accent role precisely to keep
+   * that yellow out of text: #FFAF00 is 1.78:1 on this surface, where these
+   * markers are 10px. --color-accent is the interactive ink, at 14.86:1. */
+  color: var(--color-accent);
 }
 .field-report-foot {
   display: flex;