Pre-run Scripts and Live Diffs

#Run pre-run commands before automation sessions start

Automations can now run a pre-run script on the VM before the agent starts working. This makes it much easier to check prerequisites, bootstrap dependencies, or set up project state before a run begins, and Tembo will stop the workflow early if the script fails.

#Workspace diffs now update live while a session is running

The workspace changes panel now updates live while the agent is editing files instead of waiting on polling. You can watch file counts and diff stats move in near real time and jump into a PR faster once the session is ready.

Also various bug fixes and improvements as always :)