feat: initial website commit + installation guide page

- Full nixpanel-website monorepo: web (React/Vite) + api (Fastify)
- Add /install page with one-liner, manual steps, requirements,
  software table, firewall ports, service management, and update/uninstall
- Add Install link to header nav and footer
- Add 'Install guide' CTA button to home page hero
- Add 'outline' variant to Button component
- Add .gitignore and .gitattributes

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

web/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "nixpanel-website-web",
+  "version": "1.0.0",
+  "type": "module",
+  "scripts": {
+    "dev":     "vite",
+    "build":   "tsc && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "react":              "^18.3.1",
+    "react-dom":          "^18.3.1",
+    "react-router-dom":   "^6.24.1",
+    "axios":              "^1.7.2",
+    "zustand":            "^4.5.4",
+    "@stripe/stripe-js":  "^4.1.0"
+  },
+  "devDependencies": {
+    "@types/react":         "^18.3.3",
+    "@types/react-dom":     "^18.3.0",
+    "@vitejs/plugin-react": "^4.3.1",
+    "typescript":           "^5.5.3",
+    "vite":                 "^5.3.4",
+    "tailwindcss":          "^3.4.6",
+    "autoprefixer":         "^10.4.19",
+    "postcss":              "^8.4.39"
+  }
+}