feat(#607): rebuild get-shit-done-cc → gsd-core migration (per-package cache + installer auto-cleanup + --dry-run) (#611)

* feat(#607): rebuild get-shit-done-cc → gsd-core migration

Leftover get-shit-done-cc installs poisoned the shared update cache,
causing a permanent false "update available". Rebuild the migration so a
stale old install is both harmless and actively removed.

- Per-package update cache filename (gsd-update-check-<slug>.json) in the
  shared ~/.cache/gsd dir, single-sourced via package-identity; writers
  stamp package_name and readers reject foreign/absent lineage. Multi-
  runtime visibility preserved (same shared dir + filename across runtimes).
- New get-shit-done/bin/lib/legacy-cleanup.cjs seam: detects code-file
  references to the old package + the legacy fixed-name cache across home
  runtime dirs; installer auto-cleans on every install; --dry-run previews
  and mutates nothing. User hooks and dev-preferences are never touched.
- update.md cache-clear globs gsd-update-check*.json across ALL supported
  runtimes (adds cursor/windsurf/augment/trae/qwen/hermes/codebuddy/cline).
- Fix worker MODULE_NOT_FOUND post-install (ship managed-hooks-registry.cjs
  + degrade gracefully) so the per-package cache is always written.
- Diataxis how-to: docs/cleanup-get-shit-done-cc.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* chore(#607): add changeset for PR #611

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix(#607): set USERPROFILE alongside HOME in dry-run install test for Windows

os.homedir() reads USERPROFILE on win32, so HOME-only isolation let the
spawned installer scan the real runner home on windows-latest. Set both.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

tests/orphaned-hooks.test.cjs

@@ -79,6 +79,24 @@ describe('orphaned hooks stale detection (#1750)', () => {
     }
   });
 
+  test('MANAGED_HOOKS is a superset of all gsd-* hooks in HOOKS_TO_COPY (all extensions)', () => {
+    // Every hook-named file in HOOKS_TO_COPY (matching the gsd-* naming pattern
+    // that the registry governs, regardless of extension) must appear in MANAGED_HOOKS.
+    // Non-hook support files like managed-hooks-registry.cjs are intentionally
+    // excluded from this check because they are not themselves hooks.
+    // This catches missing .sh entries as well as .js entries.
+    assert.ok(Array.isArray(HOOKS_TO_COPY), 'HOOKS_TO_COPY must be an array');
+    const gsdHooks = HOOKS_TO_COPY.filter(h => h.startsWith('gsd-'));
+    assert.ok(gsdHooks.length >= 5, `expected at least 5 gsd-* hooks in HOOKS_TO_COPY, got ${gsdHooks.length}`);
+
+    for (const hook of gsdHooks) {
+      assert.ok(
+        MANAGED_HOOKS.includes(hook),
+        `MANAGED_HOOKS should include '${hook}' (from HOOKS_TO_COPY) — add it to hooks/managed-hooks-registry.cjs`
+      );
+    }
+  });
+
   test('orphaned hook filenames are NOT in MANAGED_HOOKS', () => {
     const orphanedHooks = [
       'gsd-intel-index.js',