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>

data/publish_state.json

@@ -59,5 +59,22 @@
       }
     },
     "started_at": "2026-03-12T07:04:34.974425+00:00"
+  },
+  "35": {
+    "steps": {
+      "castopod": {
+        "completed_at": "2026-03-13T11:19:41.765107+00:00",
+        "episode_id": 38,
+        "slug": "episode-35-midnight-confessions-and-unexpected-revelations"
+      },
+      "youtube": {
+        "completed_at": "2026-03-13T11:42:00.428623+00:00",
+        "video_id": "fYvXLqFilLQ"
+      },
+      "social": {
+        "completed_at": "2026-03-13T11:42:11.800641+00:00"
+      }
+    },
+    "started_at": "2026-03-13T11:19:41.765079+00:00"
   }
 }