feat: add legal tabs and update header assets

Switch the legal page to tabbed EULA/privacy content with URL sync, update header styling, and migrate footer icons to Ant Design.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

package.json

@@ -12,6 +12,7 @@
   },
   "dependencies": {
     "@ant-design/cssinjs": "^2.1.2",
+    "@ant-design/icons": "^6.2.2",
     "@reduxjs/toolkit": "^2.11.2",
     "@tailwindcss/vite": "^4.2.4",
     "@tanstack/react-virtual": "^3.13.24",
@@ -27,6 +28,7 @@
     "tailwindcss": "^4.2.4"
   },
   "devDependencies": {
+    "@tailwindcss/typography": "^0.5.19",
     "@types/node": "^22.19.17",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
@@ -35,6 +37,7 @@
     "prettier": "^3.8.3",
     "typescript": "~6.0.3",
     "vite": "^8.0.11",
+    "vite-plugin-markdown": "^2.2.0",
     "vite-plugin-port-checker": "^1.0.1"
   },
   "pnpm": {