When spawning a subagent, the requesterOrigin's threadId, to, and
accountId were not forwarded to the callGateway({method:'agent'}) params.
This meant the subagent's runContext had no currentThreadTs or
currentChannelId, so resolveTelegramAutoThreadId could not auto-inject
the forum topic thread ID when the subagent used the message tool.
Changes:
- sessions-spawn-tool: pass to, accountId, threadId from requesterOrigin
- run-context: populate currentChannelId from opts.to as fallback
Fixes subagent messages landing in General Topic instead of the correct
Telegram DM topic thread.
