fix(nescope): give Xwayland the GL driver; a default browser in the image (#460)

- **nescope:** smithay spawned Xwayland with an empty environment, so
Xwayland never saw the GL driver selection the box sets
(`MESA_LOADER_DRIVER_OVERRIDE`, `GALLIUM_DRIVER`,
`__GLX_VENDOR_LIBRARY_NAME`). glamor then found no driver for the card
(`virtio_gpu: driver missing`), fell back to software, and the server
offered no GLX — any X11 client asking for a GLX visual failed
(`glXChooseVisual failed`). Those three variables are now passed
through.
- **Image:** `chromium` and `xdg-utils`, so applications that open
sign-in pages, OAuth flows or links have somewhere to send them.

Verified by hand in a box: with the nescope change, an X11 client that
previously died at `glXChooseVisual` started and drew.

apps/nescope/src/state.rs

@@ -438,7 +438,15 @@ impl NescopeState {
         let (xwayland, client) = XWayland::spawn(
             &self.display_handle,
             display,
-            std::iter::empty::<(String, String)>(),
+            // The GL selection the box was given, or Xwayland's glamor cannot
+            // find a driver for the card, falls back to software, and offers
+            // no GLX: Steam then dies on glXChooseVisual.
+            std::env::vars().filter(|(k, _)| {
+                matches!(
+                    k.as_str(),
+                    "MESA_LOADER_DRIVER_OVERRIDE" | "GALLIUM_DRIVER" | "__GLX_VENDOR_LIBRARY_NAME"
+                )
+            }),
             true,
             std::process::Stdio::null(), // XWayland stdout (very noisy)
             std::process::Stdio::null(), // XWayland stderr (very noisy)

build/Containerfile

@@ -398,6 +398,7 @@ RUN pacman -Syu --noconfirm --needed \
         python-xlib python-urllib3 python-pyzstd \
         libvpx speex libtheora libvdpau jsoncpp \
         strace lsof less \
+        chromium xdg-utils \
     && rm -f /usr/share/libalpm/hooks/dbus-reload.hook \
     && pacman -Rdd --noconfirm systemd systemd-sysvcompat \
     && pacman -Scc --noconfirm