add whale/public picks to prediction history and new API endpoint

- Add _compute_whale_public_picks() to reconstruct whale/public picks from historical bets
- Merge whale_pick, public_pick, whale_hit, public_hit into last_20_predictions
- Add get_prediction_history(limit) for lightweight prediction+accuracy data
- Add /api/prediction-history endpoint (default 100, max 500)
- Add Whale and Public columns with HIT/MISS to Last 20 table in frontend

app/server.py

@@ -45,6 +45,7 @@ class WebServer:
         self.app.router.add_get("/api/patterns", self._handle_patterns)
         self.app.router.add_get("/predictions", self._handle_predictions_page)
         self.app.router.add_get("/api/predictions", self._handle_predictions)
+        self.app.router.add_get("/api/prediction-history", self._handle_prediction_history)
         self.app.router.add_get("/ws", self._handle_ws)
         self.app.router.add_static("/static/", STATIC_DIR, name="static")
 
@@ -118,6 +119,15 @@ class WebServer:
             log.error("Prediction analysis query failed: %s", e)
             return web.json_response({"error": str(e)}, status=500)
 
+    async def _handle_prediction_history(self, request: web.Request) -> web.Response:
+        limit = min(int(request.query.get("limit", 100)), 500)
+        try:
+            data = await _run_sync(db.get_prediction_history, limit)
+            return web.json_response(data)
+        except Exception as e:
+            log.error("Prediction history query failed: %s", e)
+            return web.json_response({"error": str(e)}, status=500)
+
     async def _handle_analytics(self, request: web.Request) -> web.Response:
         period = request.query.get("period", "all")
         if period not in ("1h", "6h", "24h", "7d", "all"):