Bump Next.js to 15.1.9 + doc nav handles in-page anchors + help_info_menu

Three changes that fold into the v1.2.2 release PR:

1. AppImage: bump Next.js 15.1.6 -> 15.1.9 (CVE-2025-55182)
   GHSA-9qr9-h5gf-34mp / React2Shell is a pre-auth RCE in React Server
   Components when Server Functions deserialize attacker payloads. The
   ProxMenux Monitor ships Next.js in `output: "export"` mode behind
   Flask on :8008, so there is no runtime Next.js server and no
   "use server" directive in the source tree — the exploitable path is
   not reachable. Bumping to 15.1.9 anyway because OpenVAS and similar
   scanners flag the version string from the JS bundle regardless of
   architecture; raising the floor removes false-positive noise across
   every install. Reported by @rost43 in #219.

2. web/components/ui/doc-navigation.tsx: handle sidebar entries that
   point to in-page anchors. The Storage Share Manager sidebar has
   entries for `/docs/storage-share#host` and
   `/docs/storage-share#lxc-net` as section headers, but
   usePathname() does not include the hash so every visit collapsed
   to the parent page. As a result Next/Previous on /docs/storage-share
   stayed stuck at #host, and Next from .../lxc-mount-points/ pointed
   back at #host instead of #lxc-net. Read window.location.hash on
   mount (and on hashchange) and try the pathname+hash match before
   falling back to the pathname-only lookup. SSR hydrates with an
   empty hash and refreshes once mounted — brief render before
   hydration is the same as the previous behaviour, so no regression.

3. scripts/help_info_menu.sh: user-side improvement (mirrored from
   develop).

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

AppImage/ProxMenux-Monitor.AppImage.sha256

@@ -1 +1 @@
-097e2344675d4b21f1dd18c531c956c299a6507fbc3d0c9695418063581ba2b0
+149acc8644e7830ddccda97faa452f36f9a820c507e2c6b54fc9a7e51b9b4297

AppImage/package.json

@@ -49,7 +49,7 @@
     "geist": "^1.3.1",
     "input-otp": "1.4.1",
     "lucide-react": "^0.454.0",
-    "next": "15.1.6",
+    "next": "15.1.9",
     "next-themes": "^0.4.6",
     "react": "^19",
     "react-day-picker": "9.8.0",