docs(journal): log WATUT fix and harness v2 session

.pi/journal.md

@@ -475,3 +475,38 @@ State of the effort at capture: **Phase 2 begun, zero matrix blocks run.** Next
 follow `analysis/state/04-plan.md` §"Next actions" (WATUT → verify uncapped frametimes
 → finish S4 → B0→B14 → ship → report). `analysis/state/` itself is uncommitted — fold
 it into the next commit.
+
+## Session 2026-10-15 (b) — WATUT crash root-caused + fixed; harness v2
+
+Commits: `a84319b` (fix(mods): MidnightLib 1.10.0 + `analysis/state/`), `e18bd3c`
+(feat(bench): harness v2). Not pushed.
+
+- **WATUT crash = victim, not cause.** Fright's Delight 1.4.8 jar-in-jars MidnightLib
+  1.9.2; its `MidnightConfig.init` races under NeoForge parallel mod construction →
+  `ConcurrentModificationException` → broken mod state → `mod_resources` never loads →
+  WATUT's unguarded `reloadShaders` mixin throws on `particle.json`. Fix: standalone
+  `midnightlib` 1.10.0 (`side=both`; upstream fix 1fe69729, synchronizedMap). FML picks
+  it over the JiJ copy (log: "Attempted to select a dependency jar ... Using Mod File").
+  Verified 10/10 cold launches to world join, 0 CME, all on 1.10.0. Frightsdelight
+  doesn't touch `entries` (binary-compat risk checked). **Dedicated server still runs
+  1.9.2 until its next restart + jar install** — server-side exposure untested.
+- **Uncapped frametimes verified**: C1/S1 p50 2.9 ms, p99 9.5 ms, avg 297 fps
+  (harness v2 smoke, `~/onion-bench/results/session.jsonl`, label `smoke`). The earlier
+  60 fps row in `harness-results.csv` is void.
+- **Harness v1 was silently broken**: KDE Plasma is Wayland; xdotool into Xwayland `:1`
+  drops input when a native window has focus → no `/function`, no markers, ever. Also:
+  partial `options.txt` re-triggered the accessibility onboarding screen (blocks
+  `--world`), and FTB Backups fired ~7 s after every join (inside capture windows).
+- **Harness v2** (`analysis/client-perf/harness/bench.py`, `analyze.py`, `tests/`,
+  README): `boot --n N --join` reliability loop; `session` drives scenes via a
+  per-session generated datapack (armed only during the session, disarmed in
+  `finally`), log markers with ms timestamps, CSV picked by birth time, validity flags,
+  full metadata JSONL; `analyze.py` applies the BENCH-MATRIX win rule. 18 offline tests.
+- Bench-instance-only edits: FTB Backups `auto: false`
+  (`config/ftbbackups3-server.snbt`); harness pins in `options.txt` (re-applied per run).
+- Observed noise: the idle dedicated server uses 23–78 % of a core; amdgpu DPM is
+  `auto`; the bench window shares the owner's live desktop.
+
+Next: owner calls on noise controls (see harness README / session report), then S4
+build → B0 (`bench.py session --variant C0 --plan s1 --reps 3 --label B0`, ×3
+sessions) → matrix.

analysis/state/README.md

@@ -4,6 +4,11 @@ Captured **2026-10-14 ~23:45 EDT** (Manjaro bench machine), at git **HEAD `e5e36
 (`chore(bench): add client bench harness and Phase 2 handoff`), branch `main`, pushed.
 Pack: **217 mods**, MC **1.21.1**, NeoForge **21.1.251**.
 
+> **Update 2026-10-15 (b):** WATUT crash FIXED (`a84319b`, MidnightLib 1.10.0 — root
+> cause was a MidnightLib CME); uncapped frametimes VERIFIED; harness v2 (`bench.py`)
+> replaces `run_scene.py` (`e18bd3c`). See `.pi/journal.md` latest entry. Plan steps
+> 1–2 of `04-plan.md` are done; next is S4 build → B0.
+
 ## Where we are (one paragraph)
 
 The client-performance initiative is in **Phase 2 (benchmarking)**, which has just