Make the tag zone tall enough to equalize card heights

min-height was shorter than two rows of pills + padding, so two-row cards grew
taller than one-row cards and their dividers/titles dropped lower. Size the zone
to fully contain two rows and drop the asymmetric bottom padding; with centering,
single-row pills get even space above and below and every card's divider and
title line up.

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

frontend/src/lib/components/ArticleCard.svelte

@@ -108,7 +108,8 @@
      the zone. (The hero is its own layout and opts out.) */
   .tile .tags {
     align-items: center; align-content: center;
-    min-height: 48px; padding-bottom: 11px; margin-bottom: 2px;
+    min-height: 54px;   /* fully contains two rows of pills, so every card's
+                           tag zone is the same height regardless of pill count */
     border-bottom: 1px solid var(--line);
   }
   /* Source on its own line below the tags, left-justified, for uniformity. */