Legg til Fast-track-flashcards: 30 konsise kort + filter og dyplenke

Eget flashcard-sett (category: "fasttrack") som tester huskereglene,
skillene og eksamensfellene fra de fem Fast-track-modulene — kort og
konsist, uten ukesoverlappen.

- flashcards.json: 30 nye kort (7/5/7/7/4 per modul), alle med kort front
- flashcards.js: «Fast-track»-filter, categoryLabel, og fcInit(initialFilter)
- app.js: ruter #/flashcards/<filter> for dyplenke
- index.html: «Start flashcards →»-CTA på Fast-track-landingssiden
- style.css: stil for test-CTA

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/css/style.css

@@ -2234,3 +2234,57 @@ blockquote {
   .ft-promo__card { flex-direction: column; align-items: flex-start; gap: var(--sp-3); }
   .ft-promo__arrow { align-self: flex-end; }
 }
+
+/* Fast-track: test-CTA på landingssiden */
+.ft-test {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--sp-5);
+  margin-top: var(--sp-7);
+  padding: var(--sp-5) var(--sp-6);
+  background: var(--surface);
+  border: 1px solid var(--line);
+  border-left: 3px solid var(--accent-2);
+  border-radius: var(--radius-lg);
+}
+.ft-test__label {
+  font-family: var(--f-mono);
+  font-size: var(--s-0);
+  letter-spacing: 0.18em;
+  text-transform: uppercase;
+  color: var(--accent-2);
+  margin-bottom: 6px;
+}
+.ft-test__title {
+  font-family: var(--f-display);
+  font-weight: 400;
+  font-size: var(--s-5);
+  color: var(--ink);
+  margin-bottom: 4px;
+}
+.ft-test__title em { font-style: italic; color: var(--accent-2); }
+.ft-test__desc {
+  font-size: var(--s-1);
+  line-height: 1.55;
+  color: var(--ink-2);
+  max-width: 56ch;
+}
+.ft-test__cta {
+  flex-shrink: 0;
+  font-family: var(--f-mono);
+  font-size: var(--s-1);
+  letter-spacing: 0.04em;
+  color: var(--bg);
+  background: var(--accent-2);
+  border-radius: 99px;
+  padding: 12px 22px;
+  white-space: nowrap;
+  transition: transform 0.2s var(--ease), filter 0.2s;
+}
+.ft-test__cta:hover { transform: translateX(4px); filter: brightness(1.08); }
+
+@media (max-width: 640px) {
+  .ft-test { flex-direction: column; align-items: flex-start; }
+  .ft-test__cta { align-self: stretch; text-align: center; }
+}