refactor: unify three-exchange instance UI with shared templates

Co-authored-by: Cursor <cursoragent@cursor.com>

crypto_monitor_okx/app.py

@@ -6375,7 +6375,7 @@ def login():
             return redirect("/")
         else:
             flash("账号或密码错误")
-    return render_template("login.html")
+    return render_template("login.html", exchange_display=EXCHANGE_DISPLAY_NAME)
 
 @app.route("/logout")
 def logout():
@@ -7185,6 +7185,7 @@ def order_focus():
         selected_order=selected,
         default_timeframe=KLINE_TIMEFRAME,
         price_refresh_seconds=PRICE_REFRESH_SECONDS,
+        exchange_display=EXCHANGE_DISPLAY_NAME,
     )