🚀 Feature: Auto-cascade status from a parent issue to its sub-issues on close

Is there an existing issue for this?

• I have searched the existing issues

Summary

Plane currently has no way to automatically update sub-issue statuses when a parent issue is closed. When a parent work item is moved to a Completed or Cancelled state, its sub-issues stay as-is and must be closed one by one.

Proposal

An optional, per-project automation: when a parent issue enters a Completed or Cancelled state, its non-terminal sub-issues are automatically moved to the same resolution — recursively through the sub-issue tree.

• Direction: parent → children (v1). The reverse (all sub-issues done → parent auto-completes) would be a fast-follow, mirroring Linear's two independent toggles.
• Opt-in via a project Automations toggle (default off), consistent with the existing Auto-archive / Auto-close automations.
• Cancelled parent → sub-issues cancelled; Completed parent → sub-issues completed. Already-closed sub-issues are left untouched (idempotent).

Motivation

Common in hierarchical planning (epic → story → task): closing the parent should be able to close the tree. Linear ships this as "Auto-close parent and sub-issues"; related requests already exist here (e.g. #3137, #8512).

Are you willing to submit a PR?

• Yes, I'm willing to submit a PR for this feature.

No files or tests are named. Start by locating the existing Auto-archive and Auto-close automations and the project Automations toggle, then trace parent/sub-issue status transitions and terminal-state handling. Done means the opt-in behavior recursively applies the matching Completed or Cancelled status while leaving terminal sub-issues unchanged.