feat(client): add routing and sidebar icons

- install react-router-dom and wrap app in HashRouter to avoid dev proxy conflicts
- replace useState-based section switching with NavLink + Routes
- add lucide icons (Globe, KeyRound, Monitor, ClipboardList) to nav items
- icon opacity transitions on hover and active state via CSS

package-lock.json

@@ -20,7 +20,8 @@
         "lucide-react": "^1.7.0",
         "react": "^19.1.0",
         "react-dom": "^19.1.0",
-        "react-i18next": "^17.0.2"
+        "react-i18next": "^17.0.2",
+        "react-router-dom": "^7.14.0"
       },
       "devDependencies": {
         "@storybook/addon-a11y": "^10.3.5",
@@ -11083,6 +11084,57 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/react-router": {
+      "version": "7.14.0",
+      "resolved": "https://registry.npmjs.org/react-router/-/react-router-7.14.0.tgz",
+      "integrity": "sha512-m/xR9N4LQLmAS0ZhkY2nkPA1N7gQ5TUVa5n8TgANuDTARbn1gt+zLPXEm7W0XDTbrQ2AJSJKhoa6yx1D8BcpxQ==",
+      "license": "MIT",
+      "dependencies": {
+        "cookie": "^1.0.1",
+        "set-cookie-parser": "^2.6.0"
+      },
+      "engines": {
+        "node": ">=20.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=18",
+        "react-dom": ">=18"
+      },
+      "peerDependenciesMeta": {
+        "react-dom": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/react-router-dom": {
+      "version": "7.14.0",
+      "resolved": "https://registry.npmjs.org/react-router-dom/-/react-router-dom-7.14.0.tgz",
+      "integrity": "sha512-2G3ajSVSZMEtmTjIklRWlNvo8wICEpLihfD/0YMDxbWK2UyP5EGfnoIn9AIQGnF3G/FX0MRbHXdFcD+rL1ZreQ==",
+      "license": "MIT",
+      "dependencies": {
+        "react-router": "7.14.0"
+      },
+      "engines": {
+        "node": ">=20.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=18",
+        "react-dom": ">=18"
+      }
+    },
+    "node_modules/react-router/node_modules/cookie": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/cookie/-/cookie-1.1.1.tgz",
+      "integrity": "sha512-ei8Aos7ja0weRpFzJnEA9UHJ/7XQmqglbRwnf2ATjcB9Wq874VKH9kfjjirM6UhU2/E5fFYadylyhFldcqSidQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=18"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/express"
+      }
+    },
     "node_modules/readable-stream": {
       "version": "3.6.2",
       "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
@@ -11501,6 +11553,12 @@
         "url": "https://opencollective.com/express"
       }
     },
+    "node_modules/set-cookie-parser": {
+      "version": "2.7.2",
+      "resolved": "https://registry.npmjs.org/set-cookie-parser/-/set-cookie-parser-2.7.2.tgz",
+      "integrity": "sha512-oeM1lpU/UvhTxw+g3cIfxXHyJRc/uidd3yK1P242gzHds0udQBYzs3y8j4gCCW+ZJ7ad0yctld8RYO+bdurlvw==",
+      "license": "MIT"
+    },
     "node_modules/set-function-length": {
       "version": "1.2.2",
       "resolved": "https://registry.npmjs.org/set-function-length/-/set-function-length-1.2.2.tgz",