* fix(hooks): include guildId and channelName in message_received metadata
The message_received hook (both plugin and internal) already exposes
sender identity fields (senderId, senderName, senderUsername, senderE164)
but omits the guild/channel context. Plugins that track per-channel
activity receive NULL values for channel identification.
Add guildId (ctx.GroupSpace) and channelName (ctx.GroupChannel) to the
metadata block in both the plugin hook and internal hook dispatch paths.
These properties are already populated by channel providers (e.g. Discord
sets GroupSpace to the guild ID and GroupChannel to #channel-name) and
used elsewhere in the codebase (channels/conversation-label.ts).
* test: cover guild/channel hook metadata propagation (#26115) (thanks @davidrudduck)
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Co-authored-by: Peter Steinberger <steipete@gmail.com>
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