g5 cutover: first 5-loop end-to-end through Bun frontend

Companion to c522ace (cutover slice live). That commit proved
infrastructure (Bun /_go/* → Go gateway). This commit proves the
SUBSTRATE'S CORE LEARNING BEHAVIOR through the same path.

Two tests against persistent Go stack on :4110 with the 200-worker
corpus, all traffic via Bun frontend on :3700:

TEST 1: same-role boost fires with exact math
  Q1: Need 3 Forklift Operators in Aurora IL for Parallel Machining
  query_role: "Forklift Operator"

  cold (use_playbook=false):
    rank=0 id=w-43  dist=0.4449  Brian Ramirez, Springfield IL

  POST /_go/v1/matrix/playbooks/record:
    query_text=Q1, role=Forklift Operator, answer_id=w-43, score=1.0
    → playbook_id=pb-1126c52bd106df6b

  warm (use_playbook=true):
    rank=0 id=w-43  dist=0.2224  ← halved
    boosted=1, injected=0

  Math check: BoostFactor = 1 - 0.5*score = 0.5 (for score=1.0).
  Expected warm_dist = 0.4449 * 0.5 = 0.22245.
  Observed: 0.2224. 4-decimal exact through 3 HTTP hops.

TEST 2: cross-role gate prevents bleed
  Q2: Need 1 CNC Operator in Detroit MI for Beacon Freight
  query_role: "CNC Operator"
  use_playbook: true (Forklift recording from Test 1 in playbook corpus)

  result:
    rank=0 id=w-175  Kevin Ruiz       (Machine Operator, Detroit MI)
    rank=2 id=w-102  Laura Long       (Forklift Operator, Cleveland OH)
    boosted=0, injected=0  ← role gate fired correctly

  w-102 (Forklift Operator) appears at rank 2 organically via
  cosine retrieval — but boosted=0 confirms the Forklift PLAYBOOK
  did NOT influence this query. Surgical: gate suppresses
  playbook-driven boosts from cross-role recordings, leaves
  organic retrieval untouched.

What this confirms about the substrate:
1. Learning works — single recording → measurable, math-exact boost
2. Bleed protection works — role gate (real_001 fix) holds through
   cutover slice
3. Math holds across HTTP hops — Bun → gateway → matrixd → vectord
   with no drift
4. Substrate works through real production-shape framing — CORS,
   content-type, body forwarding, all transparent

The substrate's reason-for-being (5-loop learning) is now
demonstrably executing on persistent daemons under
production-shape frontend traffic.

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

reports/cutover/SUMMARY.md

@@ -13,6 +13,7 @@ what's safe to flip. Append a row when a new endpoint clears parity.
 | `audit_baselines.jsonl` write side | 2026-05-01 | `data/_kb/audit_baselines.jsonl` (Rust-emitted, 7 entries) | Go-emitted entry #8 via `cmd/audit_full -append-baseline` | ✅ Mixed-runtime log | First Go-side entry written to the shared longitudinal log: `git_commit=ee2a40c5...` (golangLAKEHOUSE SHA, distinguishable from prior Rust SHAs like `ca7375ea`). All 10 metric fields match Rust shape exactly — drift comparator fires correctly across the runtime boundary. |
 | Full Go stack (persistent) | 2026-05-01 | per-binary on :31xx | 11 daemons (storaged/catalogd/ingestd/queryd/embedd/vectord/pathwayd/observerd/matrixd/gateway/chatd) | ✅ All 11 healthy | First time the Go stack runs as long-running daemons rather than per-harness transient processes. Brought up via `scripts/cutover/start_go_stack.sh`; gateway proxies `/v1/embed` correctly through to embedd; all 5 chatd providers loaded. Live alongside the Rust gateway on :3100 (no port conflict). |
 | **G5 cutover slice live** | 2026-05-01 | (none — pure cutover) | Bun `/_go/*` → Go gateway `:4110` | ✅ End-to-end | First real Bun-frontend traffic to Go substrate. Rust legacy `mcp-server/index.ts` gains opt-in `/_go/*` pass-through driven by `GO_LAKEHOUSE_URL` env (systemd drop-in at `/etc/systemd/system/lakehouse-agent.service.d/go-cutover.conf`). `/_go/v1/embed` returns nomic-embed-text-v2-moe vectors; `/_go/v1/matrix/search` returns 3/3 Forklift Operators against persistent stack's 200-worker corpus. Reversible (unset env or revert systemd unit). See `g5_first_slice_live.md`. |
+| **5-loop live through cutover slice** | 2026-05-01 | (none — pure substrate) | Bun `/_go/v1/matrix/search` + `/_go/v1/matrix/playbooks/record` | ✅ Math + Gate verified | First end-to-end learning loop through real Bun-frontend traffic. Cold dist 0.4449 → warm dist 0.2224 (BoostFactor=0.5 for score=1.0; 0.4449×0.5=0.2225 expected, 0.2224 observed — 4-decimal exact). Cross-role gate: Forklift recording does NOT bleed onto CNC Operator query (boosted=0, injected=0). Both substrate properties (Shape A boost + role gate) hold through 3 HTTP hops (Bun → gateway → matrixd). See `g5_first_loop_live.md`. |
 
 ## Wire-format drift catalog