fix(reconcile): shield North Stars from the stale sweep — keep-open synced from board state (backend#1597)

[LukasWodka]

Item 1 of backend#1597 (the last live finding of the #1408 audit): stale-backlog.yml is column-blind, so a North Stars epic quiet for 6+8 weeks gets warned, auto-closed, and routed to Cancelled — a strategic priority silently archived, with nothing un-archiving it.

Rather than teaching every repo's stale-backlog copy about the board (20 files, drift surface), this syncs the exemption the sweep already honors: a new reconcile step ensures keep-open on every issue currently in North Stars (idempotent label add; label auto-created per repo). One-way by design — the label is also human-applied, so removal stays with humans. Dry-run aware; write failures fail the step per the token write rule.

Part of tracebloc/backend#1597.

🤖 Generated with Claude Code

---

Note

Medium Risk
Adds cross-repo issue label writes on a schedule; failures are fail-closed, but mistaken North Stars placement would incorrectly exempt issues from stale closure until humans fix board/labels.

Overview
Adds a kanban-reconcile step (after pulling board items, before classify) so issues in the North Stars column automatically get the keep-open label—the same exemption stale-backlog already honors—preventing long-quiet strategic epics from being warned, closed, and routed to Cancelled.

For each matching issue it creates keep-open in the repo if missing, then idempotently applies the label. Dry-run only logs intent; API write failures fail the step. Label removal is not automated (one-way sync) so manual keep-open use is not fought.

^{Reviewed by Cursor Bugbot for commit c8efe06. Bugbot is set up for automated code reviews on this repo. Configure here.}