The drop and supersession verdicts become issue state

[sameera]

As a delivery lead reading the backlog query, I want work the sequencing page declared dead to be absent from the query, so that the query is trustworthy on its own and does not need the sequencing page to correct it.

Acceptance Criteria

• Given Extend the --pr post-merge flow to member repos #197 is an open backlog stub that the page declares dropped, when this story completes, then Extend the --pr post-merge flow to member repos #197 is closed as not planned with a comment stating why the drop was decided.
• Given the page names items superseded before they were ever filed, when this story completes, then each has been confirmed to have no open issue, so no verdict is left without a home.
• Given the backlog query after this story, when it is run, then it returns no issue the page declared dropped or superseded.
• Given an item is closed as a result of this story, when the close is made, then the reason is not planned rather than completed, because nothing was delivered.

Notes

#197's drop rationale, per the page: its premise is reconciling the post-merge worktree flow with the member's pre-merge close-and-migrate choreography, but issue-sourced planning runs analyze/close from the hub against member PRs and deletes the member-unsupported gate, and #215 then removes close-and-migrate entirely — so building it invests in the path being retired.

The two never-filed items are hub-design-gate (superseded by #139) and entry-abandonment (superseded by #114). Both supersessions are already recorded on closed issues, so confirming they carry no open issue is the whole of the work — nothing new is written for them.

Ask for the backlog query rather than spelling the label out: nexus-gh config backlog-query.