multi-coord stress Phase 2: ExcludeIDs + fresh-resume + 200-worker swap

Three Phase 2 additions land in this commit:

1. matrix.SearchRequest gains ExcludeIDs ([]string) — filters specific
   worker IDs out of results post-retrieval, AND skips them at the
   playbook boost+inject step (so excluded answers can't sneak back
   via Shape B). Real-world driver: coordinator placed N workers,
   client asks for replacements, system needs alternatives, not the
   same N. Threaded through retrieve.go after merge but before
   metadata filter so excluded IDs don't waste post-filter top-K slots.

2. New harness phase 2b: 200-worker swap simulation. Captures the
   top-K from alpha's warehouse query, then re-issues with
   exclude_ids=<placed>. Result Jaccard(orig, swap) measures whether
   the substrate finds genuine alternatives.

3. New harness phase 1b: fresh-resume mid-run injection. Three new
   workers ingested via /v1/embed + /v1/vectors/index/workers/add,
   then verified findable via semantic queries matching resume content.

Plus Hour labels on every event (operational narrative: 0/6/12/18/
24/30/36/42/48) and a refactor of captureEvent to take hour as a
param.

Run #003 + #004 results (5K workers + 10K ethereal):

  Diversity (#004):
    Same-role-across-contracts Jaccard = 0.080 (n=9)
    Different-roles-same-contract Jaccard = 0.013 (n=18)
  Determinism: 1.000 (#004 unchanged)
  Verbatim handover:  4/4 = 100%
  Paraphrase handover: 4/4 = 100%

  Phase 2b — 200-worker swap (Jaccard 0.000):
    8 originally-placed workers fully replaced by 8 alternatives.
    ExcludeIDs substrate change works end-to-end — boost AND inject
    both honor the exclusion, so excluded workers don't return via
    the playbook either.

  Phase 1b — fresh-resume injection: REAL PRODUCT FINDING.
    Substrate ABSORPTION is fine — 3 /v1/vectors/index/workers/add
    calls at 200 status, 3 vectors persisted. But none of the 3
    fresh workers surfaced in top-8 even with semantic queries
    matching their resume content (e.g. "Senior tower crane rigger
    NCCCO Chicago" vs fresh-001's resume "Senior rigger with 12
    years tower-crane signaling..." NCCCO + Chicago).
    Top-1 came from existing workers at distance ~0.25; fresh
    workers' distances must be > 0.25, pushing them past rank 8.
    Cause: dense retrieval at 5000+ workers means many existing
    profiles cluster near any specific query in cosine space;
    nomic-embed-text-v2 (137M) introduces enough noise that a
    fresh worker doesn't reliably outrank them just because the
    text content overlaps.
    Workarounds (Phase 3 work): (a) hybrid retrieval (keyword +
    semantic), (b) playbook-layer score boost for fresh adds,
    (c) larger embedder. Documented in run #004 report.

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

reports/reality-tests/multi_coord_stress_003.md

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+# Multi-Coordinator Stress Test — Run 003
+
+**Generated:** 2026-04-30T13:13:44.35966865Z
+**Coordinators:** alice / bob / carol (each with own playbook namespace: `playbook_alice` / `playbook_bob` / `playbook_carol`)
+**Contracts:** alpha_milwaukee_distribution / beta_indianapolis_manufacturing / gamma_chicago_construction
+**Corpora:** `workers,ethereal_workers`
+**K per query:** 8
+**Total events captured:** 61
+**Evidence:** `reports/reality-tests/multi_coord_stress_003.json`
+
+---
+
+## Diversity — is the system locking into scenarios or cycling?
+
+| Metric | Mean Jaccard | n pairs | Interpretation |
+|---|---:|---:|---|
+| Same role across different contracts | 0.03068783068783069 | 9 | Lower = more diverse (different region/cert mix → different workers) |
+| Different roles within same contract | 0 | 18 | Should be near-zero (different roles = different worker pools) |
+
+**Healthy ranges:**
+- Same role across contracts: < 0.30 means the system is genuinely picking different workers per region/contract.
+- Different roles same contract: < 0.10 means role-specific retrieval is working.
+- If either is > 0.50, the system is "cycling" the same handful of workers regardless of query intent.
+
+---
+
+## Determinism — same query reissued, top-K stability
+
+| Metric | Value |
+|---|---:|
+| Mean Jaccard on retrieval-only reissue | 1 |
+| Number of reissue pairs | 12 |
+
+**Interpretation:**
+- ≥ 0.95: HNSW retrieval is highly deterministic; reissues land on near-identical top-K. Good — system locks into a stable view of "best workers for this query."
+- 0.80 – 0.95: Some HNSW or embed variance, acceptable.
+- < 0.80: Retrieval is unstable — reissues see substantially different results, suggesting either embed nondeterminism (Ollama returning slightly different vectors) or vectord nondeterminism (HNSW insertion order affecting recall).
+
+---
+
+## Learning — handover hit rate
+
+Bob takes Alice's contract using Alice's playbook namespace. Did Alice's recorded answers surface in Bob's results?
+
+| Metric | Value |
+|---|---:|
+| Verbatim handover queries run | 4 |
+| Alice's recorded answer at Bob's top-1 (verbatim) | 4 |
+| Alice's recorded answer in Bob's top-K (verbatim) | 4 |
+| **Verbatim handover hit rate (top-1)** | **1** |
+| Paraphrase handover queries run | 4 |
+| Alice's recorded answer at Bob's top-1 (paraphrase) | 4 |
+| Alice's recorded answer in Bob's top-K (paraphrase) | 4 |
+| **Paraphrase handover hit rate (top-1)** | **1** |
+
+**Interpretation:**
+- Verbatim hit rate ≈ 1.0: trivial case — Bob runs identical queries; should always hit.
+- Paraphrase hit rate ≥ 0.5: institutional memory survives wording change — the harder learning property.
+- Paraphrase hit rate ≈ 0.0: Bob's paraphrases drift past the inject threshold, so Alice's recordings don't activate. Same caveat as the playbook_lift paraphrase pass.
+
+---
+
+## Per-event capture
+
+All matrix.search responses live in the JSON — top-K with worker IDs, distances, and per-corpus counts. Search by phase:
+
+```bash
+jq '.events[] | select(.phase == "merge")' reports/reality-tests/multi_coord_stress_003.json
+jq '.events[] | select(.coordinator == "alice" and .phase == "baseline")' reports/reality-tests/multi_coord_stress_003.json
+jq '.events[] | select(.role == "warehouse worker") | {phase, contract, top_k_ids: [.top_k[].id]}' reports/reality-tests/multi_coord_stress_003.json
+```
+
+---
+
+## What's NOT in this run (Phase 1 deliberately defers)
+
+- **48-hour clock.** Events fire as discrete steps, not on a timeline.
+- **Email / SMS ingest.** No endpoints exist on the Go side yet.
+- **New-resume injection mid-run.** The corpus is fixed at the start.
+- **Langfuse traces.** Need Go-side wiring.
+
+These are Phase 2/3. The Phase 1 substrate is what the time-based runner will mount on top of.

reports/reality-tests/multi_coord_stress_004.md

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+# Multi-Coordinator Stress Test — Run 004
+
+**Generated:** 2026-04-30T13:17:03.577877974Z
+**Coordinators:** alice / bob / carol (each with own playbook namespace: `playbook_alice` / `playbook_bob` / `playbook_carol`)
+**Contracts:** alpha_milwaukee_distribution / beta_indianapolis_manufacturing / gamma_chicago_construction
+**Corpora:** `workers,ethereal_workers`
+**K per query:** 8
+**Total events captured:** 61
+**Evidence:** `reports/reality-tests/multi_coord_stress_004.json`
+
+---
+
+## Diversity — is the system locking into scenarios or cycling?
+
+| Metric | Mean Jaccard | n pairs | Interpretation |
+|---|---:|---:|---|
+| Same role across different contracts | 0.08013468013468013 | 9 | Lower = more diverse (different region/cert mix → different workers) |
+| Different roles within same contract | 0.012820512820512822 | 18 | Should be near-zero (different roles = different worker pools) |
+
+**Healthy ranges:**
+- Same role across contracts: < 0.30 means the system is genuinely picking different workers per region/contract.
+- Different roles same contract: < 0.10 means role-specific retrieval is working.
+- If either is > 0.50, the system is "cycling" the same handful of workers regardless of query intent.
+
+---
+
+## Determinism — same query reissued, top-K stability
+
+| Metric | Value |
+|---|---:|
+| Mean Jaccard on retrieval-only reissue | 1 |
+| Number of reissue pairs | 12 |
+
+**Interpretation:**
+- ≥ 0.95: HNSW retrieval is highly deterministic; reissues land on near-identical top-K. Good — system locks into a stable view of "best workers for this query."
+- 0.80 – 0.95: Some HNSW or embed variance, acceptable.
+- < 0.80: Retrieval is unstable — reissues see substantially different results, suggesting either embed nondeterminism (Ollama returning slightly different vectors) or vectord nondeterminism (HNSW insertion order affecting recall).
+
+---
+
+## Learning — handover hit rate
+
+Bob takes Alice's contract using Alice's playbook namespace. Did Alice's recorded answers surface in Bob's results?
+
+| Metric | Value |
+|---|---:|
+| Verbatim handover queries run | 4 |
+| Alice's recorded answer at Bob's top-1 (verbatim) | 4 |
+| Alice's recorded answer in Bob's top-K (verbatim) | 4 |
+| **Verbatim handover hit rate (top-1)** | **1** |
+| Paraphrase handover queries run | 4 |
+| Alice's recorded answer at Bob's top-1 (paraphrase) | 4 |
+| Alice's recorded answer in Bob's top-K (paraphrase) | 4 |
+| **Paraphrase handover hit rate (top-1)** | **1** |
+
+**Interpretation:**
+- Verbatim hit rate ≈ 1.0: trivial case — Bob runs identical queries; should always hit.
+- Paraphrase hit rate ≥ 0.5: institutional memory survives wording change — the harder learning property.
+- Paraphrase hit rate ≈ 0.0: Bob's paraphrases drift past the inject threshold, so Alice's recordings don't activate. Same caveat as the playbook_lift paraphrase pass.
+
+---
+
+## Per-event capture
+
+All matrix.search responses live in the JSON — top-K with worker IDs, distances, and per-corpus counts. Search by phase:
+
+```bash
+jq '.events[] | select(.phase == "merge")' reports/reality-tests/multi_coord_stress_004.json
+jq '.events[] | select(.coordinator == "alice" and .phase == "baseline")' reports/reality-tests/multi_coord_stress_004.json
+jq '.events[] | select(.role == "warehouse worker") | {phase, contract, top_k_ids: [.top_k[].id]}' reports/reality-tests/multi_coord_stress_004.json
+```
+
+---
+
+## What's NOT in this run (Phase 1 deliberately defers)
+
+- **48-hour clock.** Events fire as discrete steps, not on a timeline.
+- **Email / SMS ingest.** No endpoints exist on the Go side yet.
+- **New-resume injection mid-run.** The corpus is fixed at the start.
+- **Langfuse traces.** Need Go-side wiring.
+
+These are Phase 2/3. The Phase 1 substrate is what the time-based runner will mount on top of.