Merge feature/btc-history-chart: BTC candlestick chart with local OHLC storage

Resolves conflicts: combined admin + candles routers in main.py,
fixed docker-compose port to 3001:3001, restored admin styles in Dashboard.

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

btc-portfolio/backend/app/main.py

@@ -2,8 +2,8 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 from sqlalchemy import text
 
-from .database import engine, Base
-from .routes import users, purchases, stats, history, admin
+from .database import engine, Base, SessionLocal
+from .routes import users, purchases, stats, history, admin, candles
 
 Base.metadata.create_all(bind=engine)
 
@@ -22,16 +22,26 @@ app.include_router(purchases.router)
 app.include_router(stats.router)
 app.include_router(history.router)
 app.include_router(admin.router, prefix="/admin")
+app.include_router(candles.router)
 
 
 @app.on_event("startup")
-def migrate():
+def startup():
+    # Schema migration: add is_admin column if missing
     with engine.connect() as conn:
         cols = [r[1] for r in conn.execute(text("PRAGMA table_info(users)"))]
         if "is_admin" not in cols:
             conn.execute(text("ALTER TABLE users ADD COLUMN is_admin BOOLEAN DEFAULT 0"))
             conn.commit()
 
+    # Seed / refresh BTC candle data
+    from .services.candles import refresh_latest_candles
+    db = SessionLocal()
+    try:
+        refresh_latest_candles(db)
+    finally:
+        db.close()
+
 
 @app.get("/")
 def root():