materializer + replay ports + vectord substrate fix verified at scale

Two threads landing together — the doc edits interleave so they ship
in a single commit.

1. **vectord substrate fix verified at original scale** (closes the
   2026-05-01 thread). Re-ran multitier 5min @ conc=50: 132,211
   scenarios at 438/sec, 6/6 classes at 0% failure (was 4/6 pre-fix).
   Throughput dropped 1,115 → 438/sec because previously-broken
   scenarios now do real HNSW Add work — honest cost of correctness.
   The fix (i.vectors side-store + safeGraphAdd recover wrappers +
   smallIndexRebuildThreshold=32 + saveTask coalescing) holds at the
   footprint that originally surfaced the bug.

2. **Materializer port** — internal/materializer + cmd/materializer +
   scripts/materializer_smoke.sh. Ports scripts/distillation/transforms.ts
   (12 transforms) + build_evidence_index.ts (idempotency, day-partition,
   receipt). On-wire JSON shape matches TS so Bun and Go runs are
   interchangeable. 14 tests green.

3. **Replay port** — internal/replay + cmd/replay +
   scripts/replay_smoke.sh. Ports scripts/distillation/replay.ts
   (retrieve → bundle → /v1/chat → validate → log). Closes audit-FULL
   phase 7 live invocation on the Go side. Both runtimes append to the
   same data/_kb/replay_runs.jsonl (schema=replay_run.v1). 14 tests green.

Side effect on internal/distillation/types.go: EvidenceRecord gained
prompt_tokens, completion_tokens, and metadata fields to mirror the TS
shape the materializer transforms produce.

STATE_OF_PLAY refreshed to 2026-05-02; ARCHITECTURE_COMPARISON decisions
tracker moves the materializer + replay items from _open_ to DONE and
adds the substrate-fix scale verification row.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/ARCHITECTURE_COMPARISON.md

@@ -46,10 +46,11 @@ Don't:
 | 2026-05-01 | Add LRU embed cache to Rust aibridge | Closes 236× perf gap. **DONE** (commit `150cc3b` in lakehouse). |
 | 2026-05-01 | Port FillValidator + EmailValidator to Go | Production safety net Go was missing. **DONE** (commit `b03521a` in golangLAKEHOUSE). |
 | 2026-05-01 | Multi-tier load test against 100k corpus | 335k scenarios in 5min, 4/6 at 0% fail. Surfaced coder/hnsw v0.6.1 bug. Recover guard added. **DONE** (multitier_100k.md). |
-| _open_ | **coder/hnsw v0.6.1 small-index panic** | Surfaced by multi-tier test. Operator recovery: DELETE + recreate playbook_memory. Real fix: upstream patch OR custom small-index Add path OR alternate store for playbook_memory. |
+| 2026-05-01 | **coder/hnsw v0.6.1 panic — REAL FIX landed** | Lifted source-of-truth out of coder/hnsw via `i.vectors map[string][]float32` side store + `safeGraphAdd`/`safeGraphDelete` recover wrappers + warm-path rebuild fallback. Re-run: 0 failures across 19,622 scenarios (was 96-98% on 2/6). **DONE.** Architecture invariant in STATE_OF_PLAY "DO NOT RELITIGATE". |
+| 2026-05-02 | **Substrate fix verified at original failure scale** | Re-ran multitier 5min @ conc=50 (the footprint that originally surfaced the bug at 96-98% fail). Result: 132,211 scenarios at 438/sec, **6/6 classes at 0% failure**. Throughput dropped 1,115/sec → 438/sec because broken scenarios now do real HNSW Add work. Tails healthy: surge_fill_validate p99=1.53s, playbook_record_replay p99=2.32s. **Fix scales — closing the open thread.** |
 | _open_ | Drop Python sidecar from Rust aibridge | Universal-win architectural cleanup. ~200 LOC, removes 1 runtime + 1 process. |
-| _open_ | Port Rust materializer to Go (transforms.ts) | Unblocks Go-only end-to-end pipeline. ~500-800 LOC. |
-| _open_ | Port Rust replay tool to Go | Closes audit-FULL phase 7 live invocation. ~400-600 LOC. |
+| 2026-05-02 | **Port Rust materializer to Go (transforms.ts) — DONE** | `internal/materializer` + `cmd/materializer` + `materializer_smoke.sh`. Ports `transforms.ts` (12 transforms) + `build_evidence_index.ts`. Idempotency, day-partition, receipt. 14 tests green; on-wire JSON matches TS so both runtimes interoperate. |
+| 2026-05-02 | **Port Rust replay tool to Go — DONE** | `internal/replay` + `cmd/replay` + `replay_smoke.sh`. Ports `replay.ts` retrieve → bundle → /v1/chat → validate → log. Closes audit-FULL phase 7 live invocation on Go side. 14 tests green; same `data/_kb/replay_runs.jsonl` shape (schema=replay_run.v1) as TS. |
 | _open_ | Decide on Lance vector backend | Defer until corpus exceeds ~5M rows. |
 | _open_ | Pick Go primary vs Rust primary | Both viable. Go has perf edge after today; Rust has production deploy + producer-side completeness. |
 
@@ -310,6 +311,9 @@ Append entries here when this doc gets updated. One-line entries; link to commit
 - 2026-05-01 — Recorded Go validator port shipping (`b03521a` golangLAKEHOUSE), updated production-validators section.
 - 2026-05-01 — Reframed as living document in `docs/`, added Decisions tracker + Update guidance + Change log sections.
 - 2026-05-01 — Multi-tier 100k load test ran (335k scenarios @ 1,115/sec, 4/6 at 0% fail), surfaced coder/hnsw v0.6.1 nil-deref on small playbook_memory index. Recover guard added; real fix open.
+- 2026-05-01 (later) — coder/hnsw v0.6.1 panic real fix landed: vectord lifts source-of-truth out of coder/hnsw via `i.vectors` side store + recover wrappers + rebuild fallback. Re-run multitier 60s/conc=50: 0 failures across 19,622 scenarios. STATE_OF_PLAY invariant added to "DO NOT RELITIGATE".
+- 2026-05-02 — Substrate fix verified at original failure-surfacing scale. Multitier 5min @ conc=50: 132,211 scenarios at 438/sec, 6/6 classes at 0% failure (was 4/6 pre-fix). Throughput drop (1,115 → 438/sec) is the honest cost of the formerly-broken scenarios doing real HNSW Add work. STATE_OF_PLAY refreshed to 2026-05-02.
+- 2026-05-02 — Materializer + replay tool ported from Rust legacy to Go (`internal/materializer` + `internal/replay`, both with CLI + smoke + tests). Both runtimes now produce the same `data/evidence/YYYY/MM/DD/*.jsonl` and `data/_kb/replay_runs.jsonl` shapes; Go side no longer needs Bun for these phases.
 
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