Previously, if the Gst/GstApp/Cogl GI typelibs couldn't be loaded (e.g.
gst-plugins-base/good not installed, only the bare gstreamer package),
the only sign was a warning buried in the shell's log — the live
wallpaper page looked fully functional and silently did nothing.
Preferences now probes for the same bindings the running extension
needs and shows a warning row with the exact import error plus
per-distro install commands, and greys out the controls that only
matter once GStreamer is actually available. Extracted the shared
probing logic into lib/gstreamerAvailability.js so extension.js and
prefs.js (separate processes) don't duplicate it.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019RDqbdjsiisSU7CbQke4g8
