Expand all caller topic pools, add cross-episode topic dedup, publish ep35

Massively expanded all 8 caller topic pools from ~1200 to ~2500 entries to
reduce repeat calls. Added persistent topic history (data/used_topics_history.json)
with 30-day aging to prevent cross-episode duplicates. Published episode 35.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

website/css/style.css

@@ -1347,6 +1347,15 @@ a:hover {
   box-shadow: 0 4px 24px rgba(232, 121, 29, 0.12);
 }
 
+.clip-card-thumb {
+  position: absolute;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+}
+
 .clip-card-inner iframe {
   position: absolute;
   top: 0;