Hyprland exec-once runs before the session is ready

exec-once fires during Hyprland init, before the full session environment is up. Commands that rely on runtime resolution — like xdg-terminal-exec or unexported env vars — may silently fail even though the same command works fine as a keybind.

Keybinds run later when the session is fully initialized. If a keybind works but exec-once doesn't, hardcode the binary:

# May fail — $TERMINAL might not resolve yet
exec-once = [workspace 1 silent] uwsm-app -- xdg-terminal-exec

# Works reliably
exec-once = [workspace 1 silent] uwsm-app -- alacritty --config-file ~/.config/alacritty/alacritty-tmux.toml