ci: add GitHub Pages deployment workflow

Add GitHub Actions workflow for automatic deployment to GitHub Pages. Includes build and deploy jobs with pnpm setup and caching. Also update package.json with deploy scripts and vite.config.ts with base URL configuration for production.

package.json

@@ -7,7 +7,9 @@
     "dev": "vite",
     "build": "tsc -b && vite build",
     "lint": "eslint .",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "deploy": "pnpm build && gh-pages -d dist",
+    "predeploy": "pnpm build"
   },
   "dependencies": {
     "@reduxjs/toolkit": "^2.9.0",