fix: preserve thread context for cronjob deliver=origin

When a cronjob is created from within a Telegram or Slack thread,
deliver=origin was posting to the parent channel instead of the thread.

Root cause: the gateway never set HERMES_SESSION_THREAD_ID in the
session environment, so cronjob_tools.py could not capture thread_id
into the job's origin metadata — even though the scheduler already
reads origin.get('thread_id').

Fix:
- gateway/run.py: set HERMES_SESSION_THREAD_ID when thread_id is
  present on the session context, and clear it in _clear_session_env
- tools/cronjob_tools.py: read HERMES_SESSION_THREAD_ID into origin

Closes #1219

gateway/run.py

@@ -3502,10 +3502,12 @@ class GatewayRunner:
         os.environ["HERMES_SESSION_CHAT_ID"] = context.source.chat_id
         if context.source.chat_name:
             os.environ["HERMES_SESSION_CHAT_NAME"] = context.source.chat_name
+        if context.source.thread_id:
+            os.environ["HERMES_SESSION_THREAD_ID"] = str(context.source.thread_id)
     
     def _clear_session_env(self) -> None:
         """Clear session environment variables."""
-        for var in ["HERMES_SESSION_PLATFORM", "HERMES_SESSION_CHAT_ID", "HERMES_SESSION_CHAT_NAME"]:
+        for var in ["HERMES_SESSION_PLATFORM", "HERMES_SESSION_CHAT_ID", "HERMES_SESSION_CHAT_NAME", "HERMES_SESSION_THREAD_ID"]:
             if var in os.environ:
                 del os.environ[var]