Fix candle chart staleness and show live price on today's candle

- Refresh candles on every /candles request instead of only at startup
- Patch today's candle close/high/low with the live BTC price intraday
- Synthesise today's candle from live price if CoinGecko hasn't published it yet
- Display current BTC price next to the chart title

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

btc-portfolio/backend/app/routes/candles.py

@@ -1,9 +1,12 @@
 from fastapi import APIRouter, Depends, Query
 from sqlalchemy.orm import Session
+from datetime import datetime, timezone
 
 from ..database import get_db
 from .. import models
 from ..dependencies import get_current_user
+from ..services.candles import refresh_latest_candles
+from ..services.btc import get_btc_price_eur
 
 router = APIRouter()
 
@@ -14,6 +17,9 @@ def get_candles(
     db: Session = Depends(get_db),
     current_user: models.User = Depends(get_current_user),
 ):
+    # Refresh candles on every request (no-op if DB is already current)
+    refresh_latest_candles(db)
+
     query = db.query(models.OHLCCandle).order_by(models.OHLCCandle.date.asc())
 
     if days != "all":
@@ -38,6 +44,26 @@ def get_candles(
         for c in candles_db
     ]
 
+    # Patch today's candle with the live price so it tracks intraday movement
+    today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    live_price, _ = get_btc_price_eur()
+    if live_price and candles:
+        last = candles[-1]
+        if last["date"] == today:
+            last["close"] = round(live_price, 2)
+            last["high"] = round(max(last["high"], live_price), 2)
+            last["low"] = round(min(last["low"], live_price), 2)
+        elif last["date"] < today:
+            # No candle for today yet — create a synthetic one from live price
+            prev_close = last["close"]
+            candles.append({
+                "date": today,
+                "open": prev_close,
+                "high": round(max(prev_close, live_price), 2),
+                "low": round(min(prev_close, live_price), 2),
+                "close": round(live_price, 2),
+            })
+
     purchases_db = db.query(models.Purchase).filter(
         models.Purchase.user_id == current_user.id
     ).all()