Use per-exchange PWA names and logos for instance app installs.

Show Binance/OKX/Gate 交易系统 with distinct exchange icons in manifests, apple titles, and login branding.

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

crypto_monitor_okx/static/icons/manifest.webmanifest

@@ -1,11 +1,11 @@
 {
-  "name": "交易监控复盘",
-  "short_name": "监控",
-  "description": "加密货币永续交易监控与复盘",
+  "name": "OKX 交易系统",
+  "short_name": "OKX 交易系统",
+  "description": "OKX 永续交易监控与复盘",
   "start_url": "/",
   "display": "standalone",
   "background_color": "#0b0d14",
-  "theme_color": "#0b0d14",
+  "theme_color": "#FFFFFF",
   "icons": [
     {
       "src": "/static/icons/icon-192.png",