fix(auth): scan real session credential paths for fan-out/stale detection

listSessionCredentialPaths scanned <sessions>/<folder>/.claude/.credentials.json,
but real session creds live at
<sessions>/<folder>/services/<serviceId>/.claude/.credentials.json (and under
tasks/<taskId>/...). The mismatch meant writeCredentials' fan-out and
loadFreshestCredentials' stale-copy scan silently missed every real session
file — so old refresh-token copies (family-revocation landmines) were never
overwritten and the session→canonical write-back could not converge dormant
sessions.

Rewrite it via the pure, tested collectSessionCredentialPaths that walks the
actual services/<id>/.claude and services/<id>/tasks/<id>/.claude layout.
Verified on live data: now matches all 24 real session credential files (was 0).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/token-refresh.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from 'vitest';
 
 import {
   applyUpdatedTokensToEnvContent,
+  collectSessionCredentialPaths,
   pickFreshestOAuth,
   shouldAdoptSessionOAuth,
   shouldStartTokenRefreshLoop,
@@ -134,3 +135,31 @@ describe('shouldAdoptSessionOAuth (session→canonical write-back)', () => {
     ).toBe(false);
   });
 });
+
+describe('collectSessionCredentialPaths (real session layout)', () => {
+  it('builds service group + task credential paths, not <group>/.claude', () => {
+    const tree: Record<string, string[]> = {
+      '/s': ['iger', 'javis_bot'],
+      '/s/iger/services': ['claude'],
+      '/s/iger/services/claude/tasks': ['task-1'],
+      '/s/javis_bot/services': ['claude'],
+      '/s/javis_bot/services/claude/tasks': [],
+    };
+    const paths = collectSessionCredentialPaths('/s', (dir) => tree[dir] ?? []);
+    expect(paths).toContain(
+      '/s/iger/services/claude/.claude/.credentials.json',
+    );
+    expect(paths).toContain(
+      '/s/iger/services/claude/tasks/task-1/.claude/.credentials.json',
+    );
+    expect(paths).toContain(
+      '/s/javis_bot/services/claude/.claude/.credentials.json',
+    );
+    // Must NOT use the old broken <group>/.claude path that matched nothing.
+    expect(paths).not.toContain('/s/iger/.claude/.credentials.json');
+  });
+
+  it('returns nothing when there are no session folders', () => {
+    expect(collectSessionCredentialPaths('/s', () => [])).toEqual([]);
+  });
+});

src/token-refresh.ts

@@ -186,19 +186,54 @@ function writeCredentials(accountIndex: number, creds: CredentialsFile): void {
 }
 
 /**
- * Per-group session credential file paths under <DATA_DIR>/sessions. Spawned
- * agents run with CLAUDE_CONFIG_DIR pointing at one of these dirs and hold their
- * own copy of the credentials, which Claude Code may refresh (rotate) on its own.
+ * Pure builder for the on-disk session credential paths. Spawned agents run with
+ * CLAUDE_CONFIG_DIR pointing at their session `.claude` dir and keep their own
+ * copy of the credentials, which Claude Code may refresh (rotate) on its own.
+ *
+ * The real layout is:
+ *   <sessions>/<folder>/services/<serviceId>/.claude/.credentials.json          (group session)
+ *   <sessions>/<folder>/services/<serviceId>/tasks/<taskId>/.claude/.credentials.json  (task session)
+ *
+ * (An earlier version scanned <sessions>/<folder>/.claude/... which never
+ * matched, so the fan-out and stale-copy scan silently missed every real
+ * session file.) `listDirs` is injected so this is unit-testable.
  */
+export function collectSessionCredentialPaths(
+  sessionsDir: string,
+  listDirs: (dir: string) => string[],
+): string[] {
+  const CRED = ['.claude', '.credentials.json'] as const;
+  const paths: string[] = [];
+  for (const folder of listDirs(sessionsDir)) {
+    const servicesDir = path.join(sessionsDir, folder, 'services');
+    for (const serviceId of listDirs(servicesDir)) {
+      const serviceDir = path.join(servicesDir, serviceId);
+      paths.push(path.join(serviceDir, ...CRED));
+      const tasksDir = path.join(serviceDir, 'tasks');
+      for (const taskId of listDirs(tasksDir)) {
+        paths.push(path.join(tasksDir, taskId, ...CRED));
+      }
+    }
+  }
+  return paths;
+}
+
+function listSubdirectories(dir: string): string[] {
+  try {
+    return fs
+      .readdirSync(dir, { withFileTypes: true })
+      .filter((entry) => entry.isDirectory())
+      .map((entry) => entry.name);
+  } catch {
+    return [];
+  }
+}
+
 function listSessionCredentialPaths(): string[] {
   const sessionsDir = path.join(DATA_DIR, 'sessions');
   try {
     if (!fs.existsSync(sessionsDir)) return [];
-    return fs
-      .readdirSync(sessionsDir)
-      .map((group) =>
-        path.join(sessionsDir, group, '.claude', '.credentials.json'),
-      );
+    return collectSessionCredentialPaths(sessionsDir, listSubdirectories);
   } catch (err) {
     logger.warn(
       { err: getErrorMessage(err) },