test: phantom-hooks heal coverage — incident facsimile, per-item safety, lock, canonical tripwires

- gstack-settings-hook-schema-aware: 16 new cases — identity re-point (tag
  restore), foreign-basename rejection, mixed-entry per-item safety for
  add-event/remove-source/--all, prune-stale modes incl. bash-prefix +
  Windows-backslash + spaced-path idempotence, duplicate collapse preferring
  the tagged twin, plan_tune_hooks:no split, backup-on-change no-churn,
  fail-closed corrupt-JSON for every mutator, stale-lock takeover,
  fresh-foreign-lock skip, two-writer concurrency smoke, and an INCIDENT
  FACSIMILE replaying the exact 2026-08-17 production damage (6/3/2 entries,
  mixed tags, live-ephemeral Stop) healing to 2/1/1 canonical.
- NEW setup-hook-canonical-paths: static tripwires — canonical-only resolver
  (no $SOURCE_GSTACK_DIR anywhere in it), heal-before-guards ordering,
  unsuppressed heal output, ${VAR:-0} counter idiom, shared-prelude
  concatenation at every bun call site, KNOWN_HOOKS completeness vs setup's
  registrations, uninstall cleanup-before-deletion ordering, defect-class
  warning present.
- setup-plan-tune-hooks-noninteractive: PT_EXPLICIT pins + `gstack-config
  has` provenance + has-subcommand behavior (env-resolution, malformed keys).
- auq-error-fallback-hook: registration + both-teardown wiring (previously
  untested).
- uninstall: behavioral ordering test running the INSTALLED copy from inside
  the root it deletes.
- setup-windows-fallback / gstack-config-key-locale: pins updated for the new
  HOOK_CMD shape and the third C-locale validator.

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

test/auq-error-fallback-hook.test.ts

@@ -129,3 +129,36 @@ describe('hook integration — invoked as PostToolUse', () => {
     expect(out.additionalContext).toBeUndefined();
   });
 });
+
+// ----------------------------------------------------------------------
+// Registration + teardown wiring (static). Setup registers this hook under
+// its own source tag (sharing plan-tune-cathedral would overwrite the
+// question-log entry — same event+matcher); both teardown surfaces
+// (--no-team, uninstall) must remove it, which pre-v1.67.2 neither did.
+// ----------------------------------------------------------------------
+
+import * as fs from 'fs';
+
+describe('setup registration + teardown wiring (static)', () => {
+  const ROOT = path.resolve(__dirname, '..');
+  const setupSrc = fs.readFileSync(path.join(ROOT, 'setup'), 'utf-8');
+  const uninstallSrc = fs.readFileSync(path.join(ROOT, 'bin', 'gstack-uninstall'), 'utf-8');
+
+  test('setup registers the hook via the canonical resolver under --source auq-error-fallback', () => {
+    expect(setupSrc).toMatch(
+      /AUQ_ERROR_FALLBACK_HOOK="\$\(_hook_command_path hosts\/claude\/hooks\/auq-error-fallback-hook/,
+    );
+    expect(setupSrc).toContain('--source auq-error-fallback');
+  });
+
+  test('--no-team tears the hook down', () => {
+    const idx = setupSrc.indexOf('# Also tear down plan-tune');
+    expect(idx).toBeGreaterThan(-1);
+    const slice = setupSrc.slice(idx, idx + 900);
+    expect(slice).toContain('remove-source --source auq-error-fallback');
+  });
+
+  test('gstack-uninstall tears the hook down', () => {
+    expect(uninstallSrc).toContain('remove-source --source auq-error-fallback');
+  });
+});