[Automations] Conditional runs: pre-run script decides whether to create a session (exit 0 / non-zero)

Problem

A scheduled automation creates a new session on every trigger. In agent-driven pipelines most triggers are no-ops (e.g. "take the next task from a project board if one is ready"), so the sidebar accumulates empty sessions and every no-op still costs quota.

Proposal

An optional condition field for a scheduled automation: a path to a local script. When the scheduler fires, it runs the script first:

• exit 0 → create the session and run the prompt;
• exit non-zero → skip this trigger, no session is created.

Each attempt (ran / skipped) shows in the task History. The script runs in the automation's project directory, short timeout (30s) applies. That's the whole feature: one exit code decides "run or not".

Related

An agent tool to archive/delete its own completed session would clean up no-op sessions accumulated before this feature exists.

Environment: ZCode Desktop 3.11.2, macOS

No repository files, tests, or entry points are named, and this repository is described as a feedback collection project. First confirm where scheduled automations and task History are implemented; done means an optional project-local condition script runs with the stated timeout, exit 0 creates the session, non-zero skips it, and both outcomes appear in History.