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/gstack-config-key-locale.test.ts

@@ -46,13 +46,13 @@ afterEach(() => {
 });
 
 describe("gstack-config key validation is locale-independent", () => {
-  test("both get and set validate ASCII ranges under the C locale", () => {
+  test("get, has, and set all validate ASCII ranges under the C locale", () => {
     const source = fs.readFileSync(CONFIG, "utf8");
     const guardedValidators = source.match(
       /LC_ALL=C grep -qE '\^\[a-zA-Z0-9_\]\+\(@\[a-zA-Z0-9\]\+\)\?\$'/g,
     );
 
-    expect(guardedValidators).toHaveLength(2);
+    expect(guardedValidators).toHaveLength(3);
   });
 
   test("round-trips existing keys that contain i", () => {