[bug] [cef] requestFullscreen() does not fullscreen the containing native window.

Describe the bug

Calling requestFullscreen() puts the document into fullscreen within the webview, but does not fullscreen the containing native Tauri window. The native window remains decorated and keeps its original size and position.

This seems to be unimplimented as CEF DisplayHandler does not implement on_fullscreen_mode_change

Reproduction

document.documentElement.requestFullscreen();

Expected behavior

Native window enters borderless fullscreen.

Full tauri info output

[✔] Environment
    - OS: CachyOS Linux Rolling Release x86_64 (X64) (COSMIC on wayland)
    ✔ webkit2gtk-4.1: 2.52.6
    ✔ rsvg2: 2.62.3
    ✔ rustc: 1.98.1 (48a229cea 2026-09-01)
    ✔ cargo: 1.98.1 (797e8a9bc 2026-08-05)
    ✔ rustup: 1.29.1 (2026-09-01)
    ✔ Rust toolchain: stable-x86_64-unknown-linux-gnu (default)
    - node: 26.8.1
    - pnpm: 11.26.0
    - npm: 12.0.2

[-] Packages
    - tauri : git+https://github.com/tauri-apps/tauri?rev=acb57205e46de9a3e3d10c9049c4c24390192409#acb57205e46de9a3e3d10c9049c4c24390192409 (2.11.5)
    - tauri-build : git+https://github.com/tauri-apps/tauri?rev=acb57205e46de9a3e3d10c9049c4c24390192409#acb57205e46de9a3e3d10c9049c4c24390192409 (2.6.3)
    - tauri-runtime-wry : git+https://github.com/tauri-apps/tauri?rev=acb57205e46de9a3e3d10c9049c4c24390192409#acb57205e46de9a3e3d10c9049c4c24390192409 (2.11.4)
    - tauri-runtime-cef : git+https://github.com/tauri-apps/tauri?rev=acb57205e46de9a3e3d10c9049c4c24390192409#acb57205e46de9a3e3d10c9049c4c24390192409 (0.1.0), (outdated, latest: 3.0.0-alpha.0)
    - wry : 0.56.1, (outdated, latest: 0.57.0)
    - tao : 0.37.0
    - cef : 151.8.1+151.3.24, (outdated, latest: 152.3.0+152.0.6)
    - @tauri-apps/api  ⱼₛ: not installed!
    - @tauri-apps/cli  ⱼₛ: 2.11.4

[-] Plugins

[-] App
    - build-type: bundle
    - CSP: unset
    - frontendDist: ../dist
    - framework: React
    - bundler: Vite

Stack trace

Additional context

No response