feat: Implement Jupiter-style trading interface with token selection

- Add 'You're paying' and 'You're receiving' sections with proper token dropdowns
- Implement balance display and MAX button functionality
- Add automatic receiving amount calculation based on paying amount
- Enhance token selector with icons, names, and balance information
- Improve leverage position value calculations and risk warnings
- Update trade execution to use new paying/receiving token structure
- Maintain all existing functionality including stop loss, take profit, and position management

This creates a more intuitive and professional trading interface that matches Jupiter's UX patterns.

.eslintrc.json

@@ -0,0 +1,16 @@
+{
+  "extends": [
+    "next/core-web-vitals",
+    "next/typescript"
+  ],
+  "rules": {
+    "@typescript-eslint/no-unused-vars": "warn",
+    "@typescript-eslint/no-explicit-any": "warn",
+    "react/no-unescaped-entities": "warn",
+    "@next/next/no-html-link-for-pages": "warn",
+    "@next/next/no-img-element": "warn",
+    "react-hooks/exhaustive-deps": "warn",
+    "@typescript-eslint/no-require-imports": "warn",
+    "prefer-const": "warn"
+  }
+}