auditor: kb_query surfaces scrum-master reviews for files in PR diff

Wires the cohesion-plan Phase C link: the scrum-master pipeline writes
per-file reviews to data/_kb/scrum_reviews.jsonl on accept; the
auditor now reads that same file and emits one kb_query finding per
scrum review whose `file` matches a path in the PR's diff.

Severity heuristic: attempt 1-3 → info, attempt 4+ → warn. Reaching
the cloud specialist (attempt 4+) means the ladder had to escalate,
which is meaningful signal reviewers should see. Tree-split fired is
also surfaced in the finding summary.

audit.ts now passes pr.files.map(f => f.path) into runKbCheck (the
old signature dropped it on the floor). Also adds auditor/audit_one.ts
— a dry-run CLI for auditing a single PR without posting to Gitea,
useful for verifying check behavior without spamming review comments.

Verified: after writing scrum_reviews for auditor/audit.ts and
mcp-server/observer.ts (both in PR #7), audit_one 7 surfaced both as
info findings with preview + accepted_model + tree_split flag. A
scrum review for playbook_memory.rs (NOT in PR #7) was correctly
filtered out.

auditor/checks/kb_query.ts

@@ -8,6 +8,7 @@
 // What this check reads (all file-backed, append-only or periodic):
 //   data/_kb/outcomes.jsonl         — per-scenario outcomes (kb.ts)
 //   data/_kb/error_corrections.jsonl — fail→succeed deltas on same sig
+//   data/_kb/scrum_reviews.jsonl     — scrum-master accepted reviews
 //   data/_observer/ops.jsonl         — observer ring → disk stream
 //   data/_bot/cycles/*.json          — bot cycle results
 //
@@ -21,10 +22,11 @@ import type { Claim, Finding } from "../types.ts";
 const KB_DIR = "/home/profit/lakehouse/data/_kb";
 const OBSERVER_OPS = "/home/profit/lakehouse/data/_observer/ops.jsonl";
 const BOT_CYCLES_DIR = "/home/profit/lakehouse/data/_bot/cycles";
+const SCRUM_REVIEWS_JSONL = "/home/profit/lakehouse/data/_kb/scrum_reviews.jsonl";
 const TAIL_LINES = 500;
 const MAX_BOT_CYCLE_FILES = 30;
 
-export async function runKbCheck(claims: Claim[]): Promise<Finding[]> {
+export async function runKbCheck(claims: Claim[], prFiles: string[] = []): Promise<Finding[]> {
   const findings: Finding[] = [];
 
   // 1. Recent scenario outcomes: are strong-claim-style phrases showing
@@ -48,6 +50,15 @@ export async function runKbCheck(claims: Claim[]): Promise<Finding[]> {
   const obsFindings = await checkObserverStream();
   findings.push(...obsFindings);
 
+  // 5. Scrum-master reviews — surface prior accepted reviews for any
+  //    file in this PR's diff. Cohesion plan Phase C wire: the
+  //    auditor gets to "borrow" the scrum-master's deeper per-file
+  //    analysis instead of re-doing that work.
+  if (prFiles.length > 0) {
+    const scrumFindings = await checkScrumReviews(prFiles);
+    findings.push(...scrumFindings);
+  }
+
   return findings;
 }
 
@@ -181,3 +192,54 @@ function observerBySource(ops: any[]): string {
   }
   return Object.entries(c).sort((a, b) => b[1] - a[1]).map(([k, v]) => `${k}=${v}`).join(", ") || "empty";
 }
+
+// Scrum-master reviews — the scrum pipeline writes one row per
+// accepted per-file review. We match reviews whose `file` matches
+// any path in the PR's diff, then surface the *preview* + which
+// model the escalation ladder had to reach. If the scrum-master
+// needed the 123B specialist or larger to resolve a file, that's
+// a meaningful signal about the code's complexity — and it's
+// surfaced to the PR without the auditor having to re-run the
+// escalation ladder itself.
+async function checkScrumReviews(prFiles: string[]): Promise<Finding[]> {
+  const rows = await tailJsonl<any>(SCRUM_REVIEWS_JSONL, TAIL_LINES);
+  if (rows.length === 0) return [];
+
+  // Match by exact file OR filename suffix — PR files arrive as
+  // `auditor/audit.ts`-style relative paths; scrum stores the same.
+  const norm = (p: string) => p.replace(/^\/+/, "").replace(/^home\/profit\/lakehouse\//, "");
+  const prSet = new Set(prFiles.map(norm));
+
+  // Keep only the most recent review per file (last-wins).
+  const latestByFile = new Map<string, any>();
+  for (const r of rows) {
+    const f = norm(String(r.file ?? ""));
+    if (!f) continue;
+    if (!prSet.has(f)) continue;
+    latestByFile.set(f, r);
+  }
+  if (latestByFile.size === 0) return [];
+
+  const findings: Finding[] = [];
+  for (const [file, r] of latestByFile) {
+    const model = String(r.accepted_model ?? "?");
+    const attempt = r.accepted_on_attempt ?? "?";
+    const treeSplit = !!r.tree_split_fired;
+    // Heuristic: if the scrum-master had to escalate past attempt 3,
+    // or had to tree-split, that's context the PR reviewer should see.
+    // Severity: info for low-escalation, warn if escalated far up
+    // the ladder (cloud specialist required).
+    const heavyEscalation = Number(attempt) >= 4;
+    const sev: "warn" | "info" = heavyEscalation ? "warn" : "info";
+    findings.push({
+      check: "kb_query",
+      severity: sev,
+      summary: `scrum-master review for \`${file}\` — accepted on attempt ${attempt} by \`${model}\`${treeSplit ? " (tree-split)" : ""}`,
+      evidence: [
+        `reviewed_at: ${r.reviewed_at ?? "?"}`,
+        `preview: ${String(r.suggestions_preview ?? "").slice(0, 300).replace(/\n/g, " ")}`,
+      ],
+    });
+  }
+  return findings;
+}