fix(#2018): use helpers.cleanup() not raw fs.rmSync in surface test; drop unused imports (#2033)

The #2018 regression test used raw fs.rmSync() in afterEach, tripping the
local/no-raw-rmsync-in-tests eslint rule (Windows-EBUSY retry budget). CI's
lint-tests job (no eslint cache) caught it on next; local --cache runs had
false-greened it. Switch to helpers.cleanup(). Also drop two unused
destructured imports (evaluateCommandExitZero, interpolate) in the
gate-predicate-evaluator test that emitted no-unused-vars warnings.

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

tests/gate-predicate-evaluator.test.cjs

@@ -22,8 +22,6 @@ const fc = require('fast-check');
 
 const {
   evaluatePredicate,
-  evaluateCommandExitZero,
-  interpolate,
   COMMAND_EXIT_ZERO_DEFAULT_TIMEOUT_MS,
   COMMAND_MAX_OUTPUT_CHARS,
   COMMAND_MAX_LENGTH,

tests/surface-empty-manifest-agents.test.cjs

@@ -13,6 +13,7 @@ const os = require('os');
 const path = require('path');
 
 const { _syncGsdDir } = require('../gsd-core/bin/lib/surface.cjs');
+const { cleanup } = require('./helpers.cjs');
 
 function tmp() { return fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-surface-empty-')); }
 
@@ -26,7 +27,7 @@ describe('#2018 — empty manifest must not delete gsd-* agents', () => {
     }
     // Staged dir is EMPTY (unresolvable manifest → nothing staged)
   });
-  afterEach(() => { try { fs.rmSync(dest, { recursive: true, force: true }); } catch {} try { fs.rmSync(staged, { recursive: true, force: true }); } catch {} });
+  afterEach(() => { cleanup(dest); cleanup(staged); });
 
   test('empty manifest → agents preserved (not deleted)', () => {
     _syncGsdDir(staged, dest, 'agents', new Map());