allowed_channels: "*" in config (or DISCORD_ALLOWED_CHANNELS="*" env var)
is meant to allow all channels, but the check was comparing numeric channel
IDs against the literal string set {"*"} via set intersection — always empty,
so every message was silently dropped.
Add a "*" short-circuit before the set intersection, consistent with every
other platform's allowlist handling (Signal, Slack, Telegram all do this).
Fixes#14920
8598746e86