When using the message tool in a Telegram DM with topics enabled,
media and text were sent to the General topic instead of the current
session topic. This happened because toolContext.currentThreadTs was
not mapped to params.threadId before the Telegram plugin action
handler read it.
Now runMessageAction injects toolContext.currentThreadTs into
params.threadId when not explicitly provided, ensuring messages
land in the correct topic.
Fixes#2777
