Add semantic fallback gap audit and budget gate (sprints 236-237)

tools/mcp/run_semantic_fallback_budget_gate.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+RUNS_ROOT="${WSTONE_RUNS_ROOT:-$ROOT_DIR/logs/taskitem_runs}"
+INCLUDE_GLOB="${WSTONE_SEMANTIC_FALLBACK_INCLUDE_GLOB:-*}"
+OUT_DIR="${1:-$RUNS_ROOT/TEST_ONLY_semantic_fallback_budget_gate_$(date +%Y%m%d_%H%M%S)}"
+MAX_RATE="${WSTONE_SEMANTIC_MAX_FALLBACK_RATE:-0.35}"
+MIN_RECORDS="${WSTONE_SEMANTIC_FALLBACK_MIN_RECORDS:-5}"
+
+mkdir -p "$OUT_DIR"
+
+python3 "$ROOT_DIR/tools/mcp/analyze_semantic_fallback_gaps.py" \
+  --runs-root "$RUNS_ROOT" \
+  --include-glob "$INCLUDE_GLOB" \
+  --out-dir "$OUT_DIR" >/dev/null
+
+if python3 "$ROOT_DIR/tools/mcp/check_semantic_fallback_budget.py" \
+  --summary "$OUT_DIR/semantic_fallback_summary.json" \
+  --out "$OUT_DIR/semantic_fallback_budget_gate.json" \
+  --max-fallback-rate "$MAX_RATE" \
+  --min-record-count "$MIN_RECORDS" >/dev/null; then
+  jq -n \
+    --arg out_dir "$OUT_DIR" \
+    --argjson gate "$(cat "$OUT_DIR/semantic_fallback_budget_gate.json")" \
+    '{status:"pass", out_dir:$out_dir, gate:$gate}'
+else
+  jq -n \
+    --arg out_dir "$OUT_DIR" \
+    --argjson gate "$(cat "$OUT_DIR/semantic_fallback_budget_gate.json")" \
+    '{status:"fail", out_dir:$out_dir, gate:$gate}'
+  exit 9
+fi