feat: static header + collapsible sidebar navigation

Replace floating pill header with static variant for authenticated
views. Add collapsible sidebar with site picker, grouped navigation
(Analytics/Infrastructure), and mobile overlay drawer. Remove
horizontal SiteNav tab bar.

package-lock.json

@@ -8,7 +8,7 @@
       "name": "pulse-frontend",
       "version": "0.15.0-alpha",
       "dependencies": {
-        "@ciphera-net/ui": "^0.2.8",
+        "@ciphera-net/ui": "^0.2.10",
         "@ducanh2912/next-pwa": "^10.2.9",
         "@phosphor-icons/react": "^2.1.10",
         "@simplewebauthn/browser": "^13.2.2",
@@ -1668,9 +1668,9 @@
       }
     },
     "node_modules/@ciphera-net/ui": {
-      "version": "0.2.8",
-      "resolved": "https://npm.pkg.github.com/download/@ciphera-net/ui/0.2.8/3a78342207ee2351625b9469ec6030033df183cc",
-      "integrity": "sha512-I6B7fE2YXjJaipmcVS60q2pzhsy/NKM4sfvHIv4awi6mcrXjGag8FznW0sI1SbsplFWpoT5iSMtWIi/lZdFhbA==",
+      "version": "0.2.10",
+      "resolved": "https://npm.pkg.github.com/download/@ciphera-net/ui/0.2.10/aeae8c3cb25cc9b5193bfba47ce2e444ac82f1d7",
+      "integrity": "sha512-yWHitk43epGjtwUxGVrKwGYZb+VtJhauy7fgmqYfDC8tq33eVlH+yOdi44J/OiWDl8ONSlt8i5Xptz3k79UuXQ==",
       "dependencies": {
         "@phosphor-icons/react": "^2.1.10",
         "class-variance-authority": "^0.7.1",