docs(ci-reds): R7's ninth occurrence

The gate verifying the previous commit redded at `gpu` with all three of
R7's required fragments, same selector and same line. Other seven stages
green; the observing commit is documentation only.

It adds a count and nothing else, which is the honest description. The
eighth occurrence's method note says the remaining candidates must be
varied inside the gate, one per run, and that is not this lane's work.
The loadavg reading is recorded as a condition, not a cause --- R7 is
not a budget row.

docs/ci-red-signatures.md

@@ -595,12 +595,25 @@ Stage 4; the lane touches no `pmacs-gpu` code at all.
 | **selector** | `-p pmacs-gpu attach::tests::managed_retry_survives_transients_and_uses_the_successful_stream` |
 | **job / flavor** | local (Linux), `cargo test --workspace --features crdt --no-fail-fast`, i.e. under full-sweep load |
 | **required fragments** | `transient sequence must attach` + `Handshake(Io(` + `BrokenPipe` (or `code: 32`) |
-| **status** | **EIGHTH OCCURRENCE 2026-08-30 — causal status still UNRESOLVED.** The eighth carries the strongest tree exclusion this row has had, and it supersedes the fifth's: two consecutive gate runs on ONE worktree whose heads differ by a single markdown file, the first all-green and the second red |
+| **status** | **NINTH OCCURRENCE 2026-08-31 — causal status still UNRESOLVED.** The eighth carries the strongest tree exclusion this row has had, and it supersedes the fifth's: two consecutive gate runs on ONE worktree whose heads differ by a single markdown file, the first all-green and the second red |
 | **what IS established** | **three** occurrences at `pmacs-gpu/src/attach.rs:1680`, the second and third with all three fragments **verified** rather than inferred; the test drives a scripted transient-then-success sequence over a real socket pair. **The added GPU test is not the mechanism** — see the third-occurrence control below |
 | **what is NOT** | whether the broken pipe is the *fixture's* writer closing early or a real retry-path defect. **This row is not a claim that it is harmless** |
 | **rerun evidence** | occurrence 1: 6 isolated runs green, plus a full `--workspace --features crdt` sweep green (113 targets). Occurrence 2: **30 green on the observing branch** (15 isolated selector, 15 full `-p pmacs-gpu`) **plus a 15-run merge-base control, also green**. Occurrence 3: 5 isolated selector runs green, 10 full `-p pmacs-gpu` runs green **with** the added test, and **1 failure in 10 with the added test `#[ignore]`d** — the first rerun in this row's history that reproduced anything. Per the rerun rule the green runs establish intermittence only; the red control run is what carries the exclusion |
 | **retirement** | hardening that removes the named mechanism plus a discriminating witness — or a diagnosis showing the fixture, not the code, closes the pipe |
 
+**Ninth occurrence — the same lane, 2026-08-31, local (Linux), `gpu`
+step**, log `20260831T141818Z-2974002`. All three required fragments,
+same selector, same `pmacs-gpu/src/attach.rs:1889`, same
+`283 passed; 1 failed`. The other seven stages were green.
+
+**Recorded, and it adds nothing but a count — deliberately.** The
+eighth occurrence's method note says the remaining candidates have to be
+varied **inside** the gate, one per run; that has not been done here and
+this lane is not the place to start. `/proc/loadavg` at the failure read
+`3.35 8.88 5.93` — a condition, recorded because U15 made load a
+measured quantity in this file, **not** a cause, and R7 is not a budget
+row. The observing commit is documentation only.
+
 **Eighth occurrence — the CRDT identity-undo lane, 2026-08-30, local
 (Linux), `gpu` step.** All three required fragments present in the
 durable log