docs: row 115 round 2 packet, the seen-before-close request test (#1609)

Candidate on base 94ece491f: 5 files, manifest 1910eb5a; only
decision-close.test.mjs changed since round 1. Mutants m1-m4 killed
(m4 is Filbert's f4); gate passed with no flakes.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

agents/darkwing/work/queue-115/r2/gate/script-queue.log

@@ -0,0 +1,36 @@
+toolchain: node v26.8.1, git version 2.55.0
+
+OK    syntax: packages/queue/src/cli.mjs
+OK    syntax: packages/queue/src/errors.mjs
+OK    syntax: packages/queue/src/io.mjs
+OK    syntax: packages/queue/src/lock.mjs
+OK    syntax: packages/queue/src/queue.mjs
+OK    syntax: packages/queue/src/review.mjs
+OK    syntax: packages/queue/src/store.mjs
+OK    syntax: packages/queue/tests/commit.test.mjs
+OK    syntax: packages/queue/tests/data.test.mjs
+OK    syntax: packages/queue/tests/dispatch.test.mjs
+OK    syntax: packages/queue/tests/gate-owner.test.mjs
+OK    syntax: packages/queue/tests/helpers.mjs
+OK    syntax: packages/queue/tests/lock.test.mjs
+OK    syntax: packages/queue/tests/migration.test.mjs
+OK    syntax: packages/queue/tests/review.test.mjs
+OK    syntax: packages/queue/tests/store.test.mjs
+OK    syntax: packages/queue/tests/write.test.mjs
+OK    syntax: packages/queue/tests/fixtures/fake-gitea.mjs
+OK    syntax: packages/queue/tests/fixtures/kill-at.mjs
+OK    syntax: packages/queue/tests/fixtures/lock-child.mjs
+OK    syntax: packages/queue/tests/fixtures/mosaic-pre-a2.sh
+OK    syntax: scripts/queue-commit.sh
+OK    syntax: scripts/git-hooks/pre-commit
+OK    syntax: scripts/mosaic
+OK    queue-commit.sh, the guard and scripts/mosaic are executable
+OK    packages/queue declares no dependencies
+ℹ tests 156
+ℹ pass 156
+ℹ fail 0
+OK    node --test packages/queue/tests/
+OK    scripts/mosaic queue help
+skip  queue verify and render --check: this checkout (/home/jwoltje/darkwing-scratch/r115/wt) is not the queue's canonical root (/mnt/storage/src/mosaic-stack)
+
+queue suite: 28 passed, 0 failed