When discord.py is not installed at import time, DISCORD_AVAILABLE=False
and the view class definitions at module bottom are skipped.
check_discord_requirements() performs a lazy install and sets
DISCORD_AVAILABLE=True but never re-ran the class definitions, causing
NameError on the first button interaction (exec approval, slash confirm, etc.).
Extract the five ui.View subclasses into _define_discord_view_classes() and
call it both at module load (when discord.py is pre-installed) and inside
check_discord_requirements() after a successful lazy install.