Lift k cap, drop ornamental reason field, scenario generator

ITEM 1 — k CAP + REASON FIELD
The hybrid_search default k was hard-coded to 10. For multi-fill events
(5× expansion, 4× emergency) that's pool=10 → propose 5-of-10, half
the candidates become the answer with no room for rejection. Executor
prompt now instructs k to scale with target_count: k = max(count*5, 20),
cap 80. Default helper bumped 10 → 20.

Fill.reason dropped from required to optional. Nothing downstream ever
consumed it — resolveWorkerIds, sealSale, retrospective all use
candidate_id and name. Models loved to write 100-150 char justifications
per fill; on 4+ fills that blew the JSON budget before the structure
closed. Test 1 run result after this change: FIRST EVER 5/5 on the
Riverfront Steel scenario, 13 total turns across 5 events. The event
that failed last run (emergency 4×Loader with truncated reason-field
continuation) now clears in 2 turns.

Progression:
  mistral baseline:                  0/5
  qwen3.5 + continuation + think:false: 4/5
  qwen3.5 + k=20 + no-reason:        5/5 ✓

ITEM 2 — SCENARIO GENERATOR (NOT YET TESTED E2E)
tests/multi-agent/gen_scenarios.ts emits N deterministic ScenarioSpecs
with varied clients (15 companies), cities (20 Midwest cities known
to exist in workers_500k), role mixes (14 industrial staffing roles,
weighted realistic), and event sequences. Each gets a unique sig_hash
so the KB populates with distinct neighbor signatures.

scripts/run_kb_batch.sh runs all generated specs sequentially against
scenario.ts, logs per-scenario outcomes, and reports KB state at the
end. Each run takes ~2-4min; 20-30 scenarios = 1-2hr unattended.

Next: test the generator+batch on a small N (3-5) to verify KB
populates correctly and pathway recommendations start getting neighbor
signal instead of cold-starts. Then item 3 (Rust re-weighting of
hybrid_search by playbook_memory success).

scripts/run_kb_batch.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+# Run all generated scenarios sequentially to populate the KB.
+# Reads tests/multi-agent/scenarios/manifest.json and feeds each file
+# to scenario.ts. Each scenario indexes into data/_kb/ automatically
+# via the end-of-run hook. Exit code: 0 if all scenarios completed
+# (event failures are NOT failures for the batch — we want the KB to
+# record both successes AND failures).
+
+set -e
+cd "$(dirname "$0")/.."
+
+export OLLAMA_CLOUD_KEY="$(python3 -c "import json; print(json.load(open('/root/llm_team_config.json'))['providers']['ollama_cloud']['api_key'])" 2>/dev/null || echo '')"
+
+MANIFEST="tests/multi-agent/scenarios/manifest.json"
+if [ ! -f "$MANIFEST" ]; then
+  echo "✗ no manifest at $MANIFEST — run: bun tests/multi-agent/gen_scenarios.ts <N>"
+  exit 1
+fi
+
+START_TS=$(date -Iseconds)
+LOG_DIR="/tmp/lakehouse_kb_batch_$(date +%s)"
+mkdir -p "$LOG_DIR"
+echo "▶ KB batch start: $START_TS, logs → $LOG_DIR"
+
+python3 -c "
+import json
+m = json.load(open('$MANIFEST'))
+for s in m['scenarios']:
+    print(s['file'])
+" | while read -r SCEN; do
+  SPEC="tests/multi-agent/scenarios/$SCEN"
+  BASE=$(basename "$SPEC" .json)
+  LOG="$LOG_DIR/${BASE}.log"
+  echo "  ▶ $SCEN"
+  bun tests/multi-agent/scenario.ts "$SPEC" > "$LOG" 2>&1 || true
+  OK=$(grep -oP '\d+/\d+ events succeeded' "$LOG" | tail -1 || echo "no-result")
+  SIG=$(grep -oP 'KB indexed: sig=\K[a-f0-9]+' "$LOG" | tail -1 || echo "-")
+  echo "    → $OK; sig=$SIG"
+done
+
+echo "▶ KB batch done: $(date -Iseconds)"
+echo "▶ KB state:"
+wc -l data/_kb/*.jsonl 2>/dev/null || true