gauntlet 2026-05-02: smoke chain + per-component scrum + parity probe

Production-readiness gauntlet exploiting the dual Rust/Go
implementation as a measurement instrument.

## Phase 1 — Full smoke chain
21/21 PASS in ~60s. Substrate intact across the full service surface.

## Phase 2 — Per-component scrum (token-volume fix)
Prior wave (165KB diff): Kimi 62 tokens out, Qwen 297 → no useful
analysis. This wave splits today's commits into 4 focused bundles
(36-71KB each):
  c1 validatord (46KB) → 0 convergent / 11 distinct
  c2 vectord substrate (36KB) → 0 convergent / 10 distinct
  c3 materializer (71KB) → 0 convergent / 6 distinct (Opus emitted
                           a BLOCK then self-retracted in same response)
  c4 replay (45KB) → 0 convergent / 10 distinct

Reviewer engagement vs prior wave: Kimi went 62 → ~250 tokens out
once bundles dropped below 60KB.

scripts/scrum_review.sh hardening:
  * Diff-size guard (warn >60KB, hard-fail >100KB,
    SCRUM_FORCE_OVERSIZE=1 override)
  * Tightened prompt — file path must appear EXACTLY as in diff
    so post-processor can grep WHERE: lines reliably
  * Auto-tally step dedupes by (reviewer, location); convergence
    counts distinct lineages (closes the prior `opus+opus+opus`
    false-convergence bug)

## Phase 3 — Cross-runtime validator parity probe (the headline finding)
scripts/cutover/parity/validator_parity.sh sends 6 identical
/v1/validate cases to Rust :3100 AND Go :4110, compares status+body.

Result: **6/6 status codes match · 5/6 body shapes diverge.**

Rust returns serde-tagged enum:   {"Schema":{"field":"x","reason":"y"}}
Go returns flat exported-fields:  {"Kind":"schema","Field":"x","Reason":"y"}

Both round-trip inside their own runtime; a caller swapping one for
the other would break parsing silently. Captured as new _open_ row
in docs/ARCHITECTURE_COMPARISON.md decisions tracker.

This is the "use the dual-implementation as a measurement instrument"
return — single-repo scrums can't catch this class of cross-runtime
drift.

## Phase 4 — Production assessment
ship-with-known-gap. Validator wire-format gap is documented, not
regressed. ~50 LOC future fix on Go side (custom MarshalJSON on
ValidationError to match Rust's serde shape).

Persistent stack config (/tmp/lakehouse-persistent.toml) gains
validatord on :3221 + persistent-validatord binary so operators
bringing up the persistent stack get the new daemon automatically.

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

docs/ARCHITECTURE_COMPARISON.md

@@ -52,6 +52,8 @@ Don't:
 | 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. |
 | 2026-05-02 | **`/v1/validate` + `/v1/iterate` HTTP surface — DONE** | `cmd/validatord` (port 3221) hosts both endpoints. `internal/validator` gains `PlaybookValidator` (3rd kind), JSONL roster loader, and the `Iterate` orchestrator + `ExtractJSON` helper. Gateway proxies `/v1/validate` + `/v1/iterate` to validatord. Closes the last "Go-primary" backlog item (architecture_comparison.md item #7). 30+ tests + `validatord_smoke.sh` 5/5 PASS. |
+| 2026-05-02 | **Cross-runtime validator parity probe — surfaced wire-format gap** | New `scripts/cutover/parity/validator_parity.sh` runs 6 identical /v1/validate cases against Rust :3100 AND Go :4110, compares status + body. Result: **6/6 status codes match (logic-level equivalence holds), 5/6 body shapes diverge.** Rust returns serde-tagged enum `{"Schema":{"field":"x","reason":"y"}}`; Go returns flat struct `{"Kind":"schema","Field":"x","Reason":"y"}`. Any caller parsing the error envelope would break in cutover. **Open**: pick a target shape (Go matching Rust is the cutover-friendly direction) and align via custom `MarshalJSON` on `ValidationError`. |
+| _open_ | **Validator wire-format alignment** | Surfaced by 2026-05-02 parity probe. Choose canonical error JSON shape, align both runtimes. ~50 LOC custom `MarshalJSON` either side. |
 | _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. |