css: replace presentational class selectors with semantic element selectors

Replace 6 CSS class selectors across tfe.css, main.css, and search.css with
semantic element-based selectors, removing the corresponding classes from the
HTML templates entirely.

tfe.css:
- .tfe-meta-list → article dl / article dl > div / article dl dt / article dl dd
- .tfe-media-block → aside figure (+ img, video, embed children)
- .tfe-file-caption → aside figcaption

main.css:
- .card__media → .home-body figure (+ img/video children and hover/motion rules)
- .card__caption → .home-body li > a > p

search.css:
- .repertoire-col > h2 → .repertoire-index section > h2

Template changes:
- tfe.php: removed class= from <dl>, <figure>, and <figcaption>
- index.php: removed class= from <figure> and <p class=card__caption>;
  stripped orphaned card__media from the gradient <div> (only --gradient needed)

No visual change — selectors match the same elements as before since the
semantic HTML was already in place from prior refactoring work.

public/assets/css/main.css

@@ -57,8 +57,8 @@
   flex: 1;
 }
 
-/* card__media is a <figure> (with image) or <div> (gradient placeholder) */
-.card__media {
+/* Media wrapper: <figure> for real images/video, <div class="card__media--gradient"> for placeholders */
+.home-body figure {
   width: 100%;
   aspect-ratio: 4/3;
   overflow: hidden;
@@ -67,8 +67,8 @@
   margin: 0; /* reset <figure> default margin */
 }
 
-.card__media img,
-.card__media video {
+.home-body figure img,
+.home-body figure video {
   width: 100%;
   height: 100%;
   object-fit: cover;
@@ -76,8 +76,8 @@
   transition: transform 0.3s ease;
 }
 
-.card:hover .card__media img,
-.card:hover .card__media video {
+.card:hover figure img,
+.card:hover figure video {
   transform: scale(1.02);
 }
 
@@ -127,8 +127,8 @@
   font-style: italic;
 }
 
-/* Card caption — <p> directly inside the <a>, below the media */
-.card__caption {
+/* Card caption — <p> directly inside the card <a> link, below the media */
+.home-body li > a > p {
   padding: 0.55rem 0.5rem 0.65rem;
   font-size: 0.88rem;
   line-height: 1.35;
@@ -226,12 +226,12 @@
 
 /* Suppress card hover scale for users who prefer reduced motion */
 @media (prefers-reduced-motion: reduce) {
-  .card__media img,
-  .card__media video {
+  .home-body figure img,
+  .home-body figure video {
     transition: none;
   }
-  .card:hover .card__media img,
-  .card:hover .card__media video {
+  .card:hover figure img,
+  .card:hover figure video {
     transform: none;
   }
   .card__media--gradient {