Expose Full Dependency Tree and Root Run ID in Policies

We are heavily using stack dependencies, and when one stack triggers many others, we need visibility into the full dependency chain inside policies.

Right now, we only have access to limited upstream information. It would be very helpful if every policy type, including notification policies, had access to the full dependency tree and the root run ID.

This would allow us to:

• Track who originally started the run

• Thread Slack notifications properly

• Reference the same root run across all dependent stacks

• Build cleaner approval and notification logic

Currently, we have to rely on workarounds and custom scripting. Having full dependency visibility in policies would simplify our setup significantly.