MainWindow_Loaded is an async void handler whose only catch was filtered to
install-folder assembly failures, so any other library-load exception escaped
and crashed Libation at startup (issue #1931). Add a general fallback catch
that logs, shows a non-fatal message, and continues with an empty grid.
Also make UpdateGridAsync rebuild the grid when GridEntries is null instead of
throwing 'Must call BindToGridAsync first', which previously wedged the grid
and spammed 'Library Size Change Error' on every auto-scan after a failed
initial bind.
Co-authored-by: rmcrackan <rmcrackan@gmail.com>
