memories, fully-clean.cases: cross-link the two superseded-head records

[d-morrison]

Closes #2912.

What

#2907 added a bullet to memories/github-mcp-tools.md on check_suite.completed events that name a superseded head, written as if the corpus had no prior record. shared/workflow/fully-clean.cases.md already carried one — ## A check_suite.completed wake at a superseded head (ucdavis/bcs#732, 2026-08-23). Neither referenced the other.

This adds one pointer in each direction, as real relative links so check-links.py validates them, and deletes nothing.

Why not consolidate

The two records measure different sessions and repositories, and the memory bullet's substantive content — the corrected "webhooks do not deliver CI success" claim, the App-suite and cancelled-suite exclusions the event declares, the lower-bound framing, and the cross-repo occurrences — is not in the case. challenge-redundant-content says merge only when nothing is lost; here something would be.

How the gap happened

The absence was asserted from a grep of memories/ plus a targeted read of one bullet — a phrase search over a subset returned nothing and was read as "the corpus lacks this". That is the grep-is-not-coverage failure verbatim, and it was mine, on #2907.

Verification

new-line-breaks run after committing, with a negative control (appended two-sentence line → exit 1; reverted → exit 0). No non-ASCII in added lines. check-links.py: no broken relative links, which covers both new cross-file links.

Disjoint from open #2913 (preferences.md, ardia, gia) — no merge-order constraint.

🤖 Generated with Claude Code

https://claude.ai/code/session_017trXKZFoCYC4kP7NKNnN6F

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Generated by Claude Code

[github-actions]

Claude finished review — View run

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No prior comments on this PR. This is a small, self-contained documentation change adding a bidirectional cross-reference between two existing case records about check_suite.completed events naming a superseded head — one in memories/github-mcp-tools.md and one in shared/workflow/fully-clean.cases.md.

I verified both quoted section titles ("A check_suite.completed wake at a superseded head" and "A check_suite.completed event can name a superseded head") exist verbatim in their respective files, and both relative markdown links (../shared/workflow/fully-clean.cases.md from memories/, ../../memories/github-mcp-tools.md from shared/workflow/) resolve correctly to real files at the expected repo-root-relative paths.

This is exactly the kind of change the repo's own run-ums-proactively.md / dupe-check discipline calls for: rather than duplicating the incident narrative in both places, it links the two so a reader following either lands on the other, and it's honest about the fact that the second bullet was written without having found the first ("this bullet was written without having found; read the two together"), consistent with learn-from-review-findings norms in this corpus.

No factual, structural, or style problems found:

• Cross-reference targets and quoted titles both check out against current file contents.
• No code touched, so no CLAUDE.md coding-style/practices rules apply.
• No prose ambiguity, broken markup, or line-wrap issues in the added lines.
• PR is open, not a draft, mergeable, and has no prior review comments to reconcile against.

Verdict

Ready for merge

Structured Review Data (JSON)

{
  "schema_version": "1.0",
  "reviewer": "claude",
  "commit_sha": "121d99a",
  "verdict": "CLEAN",
  "findings": []
}

Reviewed commit: 82c82b0

[github-actions]

💰 Cost: $0.5194 (review) — run