fix(gbrain): disable hooks for scaffolding commit to avoid harden push race

Takeover of #2545. The harden flow installs the durability post-commit
hook, then commitScaffolding commits + pushes; the hook fires on that
commit and background-pushes (pull --rebase -> index.lock), racing the
foreground push. #2545 added --no-verify, but that only skips
pre-commit/commit-msg hooks — post-commit still runs (empirically
verified). Fix: run the scaffolding commit with -c core.hooksPath=/dev/null
so no hooks fire, and correct the hook template's misleading
'Bypass: git commit --no-verify' comment.

Co-authored-by: peterostrander2 <peterostrander2@users.noreply.github.com>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/core/brain-repo-durability.ts

@@ -156,7 +156,8 @@ function renderPostCommitHook(): string {
 ${HOOK_BANNER}
 # LOCAL + untracked — NEVER commit this file. Best-effort background auto-push so
 # agent writes don't sit local-only. The real guarantee is ${HELPER_REL}.
-# Bypass: git commit --no-verify.
+# Bypass: git -c core.hooksPath=/dev/null commit … (--no-verify only skips
+# pre-commit/commit-msg hooks; post-commit hooks still run under it).
 set -euo pipefail
 
 _branch="$(git rev-parse --abbrev-ref HEAD 2>/dev/null || echo HEAD)"
@@ -729,7 +730,10 @@ function commitScaffolding(repoPath: string, branch: string, redact: (s: string)
       stdio: ['ignore', 'pipe', 'ignore'], timeout: 10_000, env: { ...process.env, ...GIT_ENV },
     }).toString().trim();
     if (!staged) return { status: 'ok', detail: 'scaffolding already committed' };
-    execFileSync('git', ['-C', repoPath, 'commit', '-m', 'chore(gbrain): install brain durability scaffolding'], {
+    // #2545: commit with hooks disabled so the just-installed post-commit hook
+    // doesn't background-push (pull --rebase → index.lock) while we push below.
+    // NOTE: --no-verify would NOT do this — it skips pre-commit/commit-msg only.
+    execFileSync('git', ['-C', repoPath, '-c', 'core.hooksPath=/dev/null', 'commit', '-m', 'chore(gbrain): install brain durability scaffolding'], {
       stdio: 'ignore', timeout: 30_000, env: { ...process.env, ...GIT_ENV },
     });
     execFileSync('git', ['-C', repoPath, ...['-c', 'http.followRedirects=false'], 'push', 'origin', `HEAD:${branch}`], {

test/brain-repo-durability.serial.test.ts

@@ -163,6 +163,21 @@ describe('hardenBrainRepo', () => {
     expect(r.steps.find(s => s.step === 'commit')).toBeUndefined();
   });
 
+  test('#2545 — scaffolding commit does not fire the post-commit hook (no push race)', async () => {
+    await harden();
+    // The gbrain hook's brain_push always writes to $GBRAIN_HOME/brain-push.log
+    // (ok / rejected / lock-timeout — every path logs). If the scaffolding
+    // commit fired the hook, the detached push races commitScaffolding's own
+    // push (pull --rebase → index.lock) and this log appears within ms.
+    await new Promise(r => setTimeout(r, 1500));
+    expect(existsSync(join(process.env.GBRAIN_HOME!, 'brain-push.log'))).toBe(false);
+    // And the hook no longer documents a bypass that doesn't work: --no-verify
+    // skips pre-commit/commit-msg only, never post-commit.
+    const hook = readFileSync(join(work, '.git', 'hooks', 'post-commit'), 'utf-8');
+    expect(hook).not.toContain('Bypass: git commit --no-verify');
+    expect(hook).toContain('core.hooksPath=/dev/null');
+  });
+
   test('dry-run makes no commit and writes no files', async () => {
     const before = commitCount(work);
     await harden({ dryRun: true });