board: retroactive hygiene for #1167/#1168 — the gate-builders skipped the gate

.claude/board/LATEST_STATE.md

@@ -1,3 +1,12 @@
+## 2026-09-04 — two mechanical board gates land, and they were shipped WITHOUT their own hygiene — INVENTORY DELTA
+
+- ADDED `.claude/tools/append_only_gate.py` + `.github/workflows/append-only-gate.yml` (#1167) — 8 protected board files, compared against `git merge-base` (not the raw base ref, which reports a shrink whenever the base moved ahead). Absent-at-base = new, silent; deleted = FAIL; unresolvable ref = fail closed with a `fetch-depth: 0` hint. Verified at four levels: 7 self-test cases (3 fire / 4 silent), the real git path against `b67f1958`, an END-TO-END fire test (`ISSUES.md` shortened 2591 → 2541 lines → exit 1), and the fail-closed arm (`origin/main~200` → exit 1).
+- ADDED `.claude/tools/citation_decay.py` + `.github/workflows/citation-decay.yml` (#1168) — a NO-NEW-DECAY gate on `path:LINE` citations, scoped to the lines a PR actually adds.
+- MEASURED backlog, which is why the scope is lines and not files: **2314 citations / 37 OK / 124 DECAYED / 2153 UNVERIFIABLE** across `.claude/plans` + `.claude/board`. File-level scoping was tried and rejected on evidence — `EPIPHANIES.md` alone carries 10 pre-existing decays and the board-hygiene rule means nearly every PR touches it, so a file-scoped gate would fire on essentially every PR. **A gate that fires on everything carries exactly as much information as one that never fires.**
+- The 93% unverifiable rate is not a defect in the scanner: the house style cites bare basenames, which no scanner can resolve to a file. That is a finding about the citation convention, not about the tool.
+- THREE defects were caught centrally rather than by the workers: the citation regex's lookbehind included `.`, so it could not match ANY `.claude/...` path — i.e. most of what this workspace actually cites, found only because a probe citation was silently ignored; the file-vs-line scoping above; and an `f.citing_line` / `f.cite_line` mismatch in my own filter patch.
+- **VIOLATION, recorded rather than quietly fixed:** both PRs added a deliverable and shipped with NO board entry in-commit. That is exactly the retroactive-hygiene anti-pattern the Mandatory Board-Hygiene Rule names, committed by the session that was building gates to make board discipline mechanical. This commit is the retroactive fix; the fact that it was needed is the entry's point.
+
 ## 2026-09-03 — branch: new plans must carry D-ids (the gate, not the backfill) — INVENTORY DELTA
 
 - ADDED `.claude/tools/plan_dids.py` — fails when a plan file carries no D-id. Reads the pattern out of `supersession_index.py`'s SOURCE rather than importing it: that module has no `__main__` guard, so `import` runs the whole generator and prints the index (measured — the first version did this). Hard-errors if the definition is renamed, rather than falling back to a local copy.

.claude/board/PR_ARC_INVENTORY.md

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+## 2026-09-04 — lance-graph PR #1167 (merged `fdc6d8a9`) + #1168 (merged `c5e84447`) — the two mechanical board gates
+
+- **Added:** `.claude/tools/append_only_gate.py` + `append-only-gate.yml` (#1167 — 8 protected files never shrink, merge-base comparison, fail-closed); `.claude/tools/citation_decay.py` + `citation-decay.yml` (#1168 — `path:LINE` citations, scoped to added lines only).
+- **Measured:** append-only gate verified at four levels incl. a real end-to-end fire (`ISSUES.md` 2591 → 2541 → exit 1) and the fail-closed arm. Citation backlog 2314 / 37 OK / 124 DECAYED / 2153 UNVERIFIABLE — the 93% unverifiable is the bare-basename house style, not a scanner defect.
+- **Locked:** line-scoping, not file-scoping — measured: `EPIPHANIES.md` alone has 10 pre-existing decays and nearly every PR touches it, so a file-scoped gate fires on everything and therefore says nothing.
+- **Deferred:** the 124-decay backlog (a separate, deliberate cleanup); a convention change that would make bare-basename citations resolvable.
+- **Violation:** both PRs shipped without board hygiene in-commit and are discharged retroactively here — noted because the subject of both PRs is making this class of lapse mechanical.
+- **Confidence:** High on both gates (each disable-verified red-then-green); Medium on the citation gate's long-run signal, since 93% of the corpus is invisible to it.
+
 > **⊘ TRUNCATION RESTORED (2026-08-30).** The #1081 hygiene commit
 > (`25b9e4c9`) destroyed this append-only file — 5876 → 32 lines — via the
 > destructive-prepend one-liner: `open(p, "w").write(entry + open(p).read())`