fix: preserve ATH/Mayer/200D SMA when CoinGecko rate-limits

- ATH: fall back to cached value when fetch fails
- 200D SMA: compute from history.json when CoinGecko blocks us
- Mayer Multiple: derived from 200D SMA fallback
- Drawdown: preserve cached value on ATH fetch failure
- Fixes N/A Drawdown and -- header stats after quick refresh

dashboard/server.py

@@ -126,18 +126,41 @@ def run_scrape(force_full=False):
 
         log.info("Fetching BTC ATH...")
         ath_data = price.fetch_ath()
-        if price_current.get("price") and ath_data.get("ath"):
-            drawdown = price.calculate_drawdown(price_current["price"], ath_data["ath"])
-            metrics["drawdown"] = {"value": drawdown, "ath": ath_data["ath"]}
+        ath_val = ath_data.get("ath") or existing_cache.get("drawdown", {}).get("ath")
+        if price_current.get("price") and ath_val:
+            drawdown = price.calculate_drawdown(price_current["price"], ath_val)
+            metrics["drawdown"] = {"value": drawdown, "ath": ath_val}
+        elif existing_cache.get("drawdown", {}).get("value") is not None:
+            log.info("ATH fetch failed — reusing cached drawdown")
+            metrics["drawdown"] = existing_cache["drawdown"]
         else:
             metrics["drawdown"] = {"value": None}
 
-        log.info("Fetching historical prices...")
+        log.info("Fetching historical prices for 200D SMA / Mayer...")
         hist = price.fetch_historical()
         if hist:
             sma_200d = price.calculate_200d_sma(hist)
             mayer = price.calculate_mayer_multiple(price_current.get("price"), sma_200d)
             metrics["price_extras"] = {"sma_200d": sma_200d, "mayer_multiple": mayer}
+        else:
+            # CoinGecko rate-limited — compute from history.json instead
+            try:
+                hist_path = os.path.join(DATA_DIR, "history.json")
+                with open(hist_path) as f:
+                    hdata = json.load(f)
+                btc_vals = hdata.get("btc_price", {}).get("values", [])
+                if len(btc_vals) >= 200:
+                    sma_200d = sum(btc_vals[-200:]) / 200
+                    cur_p = price_current.get("price") or btc_vals[-1]
+                    mayer = cur_p / sma_200d if sma_200d else None
+                    metrics["price_extras"] = {"sma_200d": sma_200d, "mayer_multiple": round(mayer, 4) if mayer else None}
+                    log.info("Computed 200D SMA from history.json (CoinGecko rate-limited)")
+                elif existing_cache.get("price_extras"):
+                    metrics["price_extras"] = existing_cache["price_extras"]
+            except Exception:
+                if existing_cache.get("price_extras"):
+                    metrics["price_extras"] = existing_cache["price_extras"]
+                    log.info("Reusing cached price_extras")
 
         # 3. On-chain metrics — use cached values (historical data is permanent)
         onchain_keys = ["puell_multiple", "mvrv_zscore", "reserve_risk", "rhodl_ratio",