fix: adversarial-review runtime fixes across the telemetry + kill paths

- session-runner: exit-labeling keys off 'exit', not 'close' — an orphan
  holding the pipes could relabel a REAL exit (auth failure) as
  'timeout_startup' availability noise; the kill path still always
  group-kills and cancels the reader (labeling and unblocking are separate
  concerns). Work phase arms on a flag, not firstResponseMs===0 (a same-ms
  first byte left the startup timer live all run). The CI startup grace is
  now a real FLOOR (Math.max), matching its name and pinning test.
- gstack-detach: pgid captured AT SPAWN (== child pid under
  start_new_session) — resolving it after the grace raised ESRCH once the
  leader died on SIGTERM, orphaning TERM-immune grandchildren forever.
- test-free-shards: ledger entries carry branch + git_sha (rev-parse split:
  '--abbrev-ref HEAD HEAD' printed the branch twice and recorded it as the
  sha); local ledger default is per-PROJECT, not the machine-global tmpdir.
- eval-flake-rank: per-LINE ledger parse (one torn JSONL line vanished the
  whole series), 60-day recency bound (transcript-bearing files are MBs),
  shared isFinalizedEvalResultFile predicate (the artifact-taxonomy rule
  lived in three places); eval-store exports the predicate and finalize
  stops computing flakyRetries twice; paid-shards cleanup uses async rm
  (a SIGKILLed shard's git-workspace teardown blocked every sibling's
  stream classification on the parent event loop).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/eval-flake-rank.ts

@@ -21,7 +21,7 @@
 
 import * as fs from 'node:fs';
 import * as path from 'node:path';
-import { getProjectEvalDir, isPartialEval, type EvalResult } from '../test/helpers/eval-store';
+import { getProjectEvalDir, isPartialEval, isFinalizedEvalResultFile, type EvalResult } from '../test/helpers/eval-store';
 import { flakeLedgerPath, type FlakeLedgerEntry } from './test-free-shards';
 
 interface TestSeries {
@@ -73,21 +73,36 @@ export function aggregate(evalFiles: string[]): Map<string, TestSeries> {
   return series;
 }
 
-export function collectEvalFiles(dir: string): string[] {
+export function collectEvalFiles(dir: string, sinceDays = 60): string[] {
   if (!fs.existsSync(dir)) return [];
+  const cutoff = Date.now() - sinceDays * 86_400_000;
   const out: string[] = [];
   for (const name of fs.readdirSync(dir, { recursive: true }) as string[]) {
-    if (!name.endsWith('.json') || path.basename(name).startsWith('_partial')) continue;
-    out.push(path.join(dir, name));
+    if (!isFinalizedEvalResultFile(name)) continue;
+    const full = path.join(dir, name);
+    try {
+      // Recency bound (review finding): E2E results embed full transcripts
+      // (MBs each) and the scan is otherwise unbounded over all-time history.
+      if (fs.statSync(full).mtimeMs < cutoff) continue;
+    } catch { continue; }
+    out.push(full);
   }
   return out;
 }
 
 function readFreeLedger(): FlakeLedgerEntry[] {
+  // Per-LINE parse: one malformed JSONL line (torn write, manual edit) must
+  // drop that line, never vanish the whole series (codex adversarial finding).
+  let raw: string;
   try {
-    return fs.readFileSync(flakeLedgerPath(), 'utf-8')
-      .split('\n').filter(Boolean).map((l) => JSON.parse(l));
+    raw = fs.readFileSync(flakeLedgerPath(), 'utf-8');
   } catch { return []; }
+  const out: FlakeLedgerEntry[] = [];
+  for (const line of raw.split('\n')) {
+    if (!line.trim()) continue;
+    try { out.push(JSON.parse(line)); } catch { /* torn line — skip */ }
+  }
+  return out;
 }
 
 if (import.meta.main) {
@@ -95,8 +110,10 @@ if (import.meta.main) {
   const dirFlag = argv.indexOf('--dir');
   const dir = dirFlag !== -1 ? argv[dirFlag + 1] : getProjectEvalDir();
   const asJson = argv.includes('--json');
+  const sinceFlag = argv.indexOf('--since-days');
+  const sinceDays = sinceFlag !== -1 ? Number(argv[sinceFlag + 1]) || 60 : 60;
 
-  const files = collectEvalFiles(dir);
+  const files = collectEvalFiles(dir, sinceDays);
   const series = [...aggregate(files).values()]
     .sort((a, b) => b.retriedPasses - a.retriedPasses || (b.fails / b.runs) - (a.fails / a.runs));
   const ledger = readFreeLedger();

scripts/test-free-shards.ts

@@ -1037,10 +1037,28 @@ export interface FlakeLedgerEntry {
   file: string;
   /** Shard the original failure surfaced in, when attributable. */
   shard?: number;
+  /** Code-state attribution (review finding): without branch/sha the series
+   *  can't tie an entry to the state that produced it, and the WS16
+   *  promotion evidence needs exactly that. */
+  branch?: string;
+  git_sha?: string;
 }
 
 export function flakeLedgerPath(env: NodeJS.ProcessEnv = process.env): string {
-  return env.GSTACK_FLAKE_LEDGER || path.join(os.tmpdir(), 'gstack-flake-ledger.jsonl');
+  if (env.GSTACK_FLAKE_LEDGER) return env.GSTACK_FLAKE_LEDGER;
+  // Local default: per-PROJECT, not the machine-global tmpdir — sibling
+  // Conductor worktrees of DIFFERENT repos must not interleave into one
+  // series (review finding). CI always sets GSTACK_FLAKE_LEDGER explicitly.
+  try {
+    const slug = spawnSync('bash', ['-c', '~/.claude/skills/gstack/bin/gstack-slug 2>/dev/null'], { stdio: 'pipe', timeout: 3000 })
+      .stdout?.toString().match(/^SLUG=(.+)$/m)?.[1];
+    if (slug) {
+      const dir = path.join(os.homedir(), '.gstack', 'projects', slug);
+      fs.mkdirSync(dir, { recursive: true });
+      return path.join(dir, 'flake-ledger.jsonl');
+    }
+  } catch { /* fall through */ }
+  return path.join(os.tmpdir(), 'gstack-flake-ledger.jsonl');
 }
 
 export function appendFlakeLedger(
@@ -1552,6 +1570,11 @@ async function main(): Promise<number> {
         // Durable record (WS1): console lines vanish with the scrollback; the
         // ledger makes repeat offenders rankable across runs (eval:flake-rank).
         const ts = new Date().toISOString();
+        // Two separate calls: `rev-parse --abbrev-ref HEAD HEAD` abbreviates
+        // BOTH revs, printing the branch twice — git_sha recorded the branch
+        // name (codex adversarial finding).
+        const ledgerBranch = (spawnSync('git', ['rev-parse', '--abbrev-ref', 'HEAD'], { cwd: ROOT, encoding: 'utf8', timeout: 5000 }).stdout ?? '').trim();
+        const ledgerSha = (spawnSync('git', ['rev-parse', 'HEAD'], { cwd: ROOT, encoding: 'utf8', timeout: 5000 }).stdout ?? '').trim();
         appendFlakeLedger(
           flakyFiles.map((file) => ({
             ts,
@@ -1559,6 +1582,8 @@ async function main(): Promise<number> {
             kind: 'flaky-pass' as const,
             file,
             shard: outcomes.find((o) => o.failingFiles.includes(file))?.shard,
+            ...(ledgerBranch ? { branch: ledgerBranch } : {}),
+            ...(ledgerSha ? { git_sha: ledgerSha.slice(0, 12) } : {}),
           })),
           flakeLedgerPath(),
         );

scripts/test-paid-shards.ts

@@ -64,7 +64,7 @@ import {
 } from './test-strict-output';
 import { PAID_TEST_GLOBS, isPaidTestFile } from '../test/helpers/paid-test-set';
 import { PERIODIC_CI_EXCLUDE } from '../test/helpers/periodic-exclude-data';
-import { getProjectEvalDir, getClaudeCliVersion } from '../test/helpers/eval-store';
+import { getProjectEvalDir, getClaudeCliVersion, isFinalizedEvalResultFile } from '../test/helpers/eval-store';
 import { preflightAnthropicApi } from '../test/helpers/anthropic-preflight';
 import {
   detectBaseBranch,
@@ -575,7 +575,11 @@ export async function runPaidShard(
     // Close the spool even when the spawn itself failed.
     await new Promise<void>((resolve) => logStream.end(() => resolve()));
     try {
-      fs.rmSync(stateDir, { recursive: true, force: true });
+      // async rm: a SIGKILLed shard can leave a full git workspace + Chromium
+      // profile here; a synchronous recursive delete on the parent's event
+      // loop would stall every sibling shard's stream classification and
+      // wall timers for seconds (review finding).
+      await fs.promises.rm(stateDir, { recursive: true, force: true });
     } catch {
       // Best-effort: a locked file must not turn a real verdict into an
       // exception (same posture as the free runner's cleanup).
@@ -1035,7 +1039,7 @@ async function main(): Promise<number> {
     // Source: the finalized eval-store JSONs inside the slice artifacts.
     const flaky: Array<{ name: string; attempts: number; file: string }> = [];
     for (const name of fs.readdirSync(options.reportDir, { recursive: true }) as string[]) {
-      if (!/\.json$/.test(name) || /manifest\.json$|slice-\d+\.json$|^_partial|\/_partial/.test(name)) continue;
+      if (!isFinalizedEvalResultFile(name)) continue;
       try {
         const parsed = JSON.parse(fs.readFileSync(path.join(options.reportDir, name), 'utf-8')) as { flaky_retries?: Array<{ name: string; attempts: number }> };
         for (const f of parsed.flaky_retries ?? []) flaky.push({ ...f, file: name });